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OF   THE 

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THE    IRISH    GAS    LIGHT    FOR    LIGHT-HOUSES— 1O8  Jets. 


43D  CONGRESS,  )  SENATE.  j  Ex.  Doc. 

1st  Session,      )  \    No.  54. 


OF  A 


TOUR    OF    INSPECTION" 


OP 


EUROPEAN  LIGHT-HOUSE  ESTABLISHMENTS, 

MADE   IN  1878, 


BY 


Major    GEOROE    H.    ELLIOT, 

OF  ENGINEERS  U.  S.  A.,  MEMBER  AXU  EXGINEEIJ- 
SECRETARY  OF  THE  LIGHT-HOUSE  BOARD, 


UNDER   THE   AUTHORITY"   OF 

Hon.  WILLIAM  A.  RICHARDSON, 

SECRETARY  OF  THE  TREASURY. 


APRIL  24,  1874.— Referred  to  the  Committee  on  Printing. 
JUNE  2,  1874. — Ordered  to  be  printed,  together  with  one  thousand 
additional  copies  for  the  use  of  the  Treasury  Department. 


WASHINGTON: 

GOVERNMENT    PRINTING    OFFICE. 
1874. 


TABLE    OF    CONTENTS. 


Page. 

Resolution  of  the  Senate  of  March  30,1874 * 7 

Letter  from  Secretary  of  the  Treasury  to  the  President  of  the  Senate 7 

Resolution  of  the  Senate  of  June  2,  1874 7 

Letter  from  Professor  Henry  to  Hon.  H.  B.  Anthony 8 

Extract  from  Light-House  Board  Report  for  1873 9 

Outward  voyage,  and   deficiency  in  fog-signals  on  transatlantic  steamers 15 

The  Trinity  House,  London 18 

Fog-signal  experiments  near  Dover,  under  direction  of  Professor  Tyndall 22 

Extracts  from  Professor  Tyuda.ll's  report 25 

Sir  Frederick  Arrow's  remarks  on  Professor  Tyudall's  report 59 

South  Foreland  electric  lights , 66 

Roman  pharos  in  Dover  Castle 72 

Examination  of  the  Doty  lamp 74 

Experiments  with  lights  in  Westminster  clock- tower 75 

Trinity-House  depot  at  Blackwall 76 

Improvements  in  lamps  for  light-houses 80 

Inspection-tour  of  the  North  Sea  lights  of  England  in  the  Trinity  House  steam- 
yacht  Vestal 99 

Iron  light-houses  off  the  mouth  of  the  Thames 99 

Orforduess  lights 101 

Depot  at  Yarmouth 101 

Haisbofough  lights 104 

Experiments  at  night  with  Haisborough  lights 109 

Newurp  light-ship 113 

Cockle  light-ship 115 

Spurn  Point  lights 115 

Flamborough  Head  light 117 

Whitby  lights ,,.. 118 

Souter  Point  light 120 

Coquet  light '. 127 

Inner  Fame  Island  lights 130 

Longstone  light 130 

'Return  to  London , 132 

Second  tour  of  inspection. — the  southwest  coast  of  England 132 

Light-house  depot  at  Isle  of  Wight 132 

Saint  Catherine  light 133 

The  Needles  light... 134 

Lights  of  the  Bill  of  Portland 135 

The  Start  light 135 

The  Eddystone  light 136 

Saint  Anthony  light 137 

Plymouth  Breakwater  light 137 

The  Lizard  lights 139 

The  Wolf  light 140 

Rundlestone  bell-buoy 144 

Seven  Stones  light-ship 145 

Longships  light 146 

Godrevy  light.   148 

"The  Stones"  buoy,  off  Godrevy 148 


4  CONTENTS. 

age.- 

Holybead  light 149 

North  Stack  fog-signal  station 155 

South  Stack  light 156 

Visit  to  Commissioners  of  Irish  Lights,  Dublin 158 

Ho  wth  Baily  light 159 

Wicklow  Headlight 160 

Gas-apparatus  for  fixed  lights 161 

Gas-apparatus  for  intermittent  lights 162 

Gas-apparatus  for  revolving  lights 165 

Gas-apparatus  for  group  flashing-  lights 165 

Gas-apparatus  for  triform  fixed  lights 166 

Gas-apparatus  for  triform  intermittent  lights 167 

Gas-apparatus  for  triform  revolving  lights 167 

Gas-apparatus  for  triform  group  flashing  lights 167 

Experiments  with  the  triform  gas-light i 167 

Illuminating  powers  of  gas-lights 169 

Cost  of  gas-light  apparatus 170 

Cost  of  gas-light  apparatus,  (triform) 171 

Cost  of  maintenance  of  gas-lights 171 

Illumination  of  beacons  by  gas 172 

Wigham's  gas-gun 174 

Visit  to  Commissioners  of  Northern  Lights,  Edinburgh 175 

Stevenson's  holophone 179 

Visit  to  lens  manufactory  of  Chance,  Brothers  &  Co 183 

Visit  to  Commission  des  Phares,  Paris 184 

D6p6t  des  Phares  of  France. 185 

M.  Reynaud's  observations  concerning  mineral  oil 193 

Lens-makers  of  Paris 203 

Lepaute's  observations  concerning  light-house  burners 208 

Light-houses  at  the  mouth  of  the  Seine 215 

Pharede  THdpital 217 

Feu  de  port  at  Honfleur 218 

Phare  de  Fatouville '. 219 

Phares  de  la  Heve 220 

Description  of  the  electric  lights  at  La  Heve 226 

International  exhibition  at  Vienna 249 

Submarine    foundations  for  harbor  light-houses 250 

Models  of  light-houses 250 

Light-house  apparatus 251 

Iron  tower  for  fourth-order  light 254 

Swedish  light-houses 257 

Austrian  fog-horn 261 

Osnaghi's  reflectors 262 

Return  voyage 266 

Conclusion 267 


LIST    OF    ILLUSTRATIONS. 


PLATES. 

Page. 

Frontispiece  :  The  Irish  gas-flame  for  light-houses 1 

I.  South  Foreland,  general  plan  of  light-houses 66 

II.  South  Foreland,  ground-plan  of  engine-house 68 

III.  South  Foreland,  lantern  and  lens  at 70 

IV.  Six-wick  Trinity  House  burner 76 

V.  Maplin  Sand  light-house 100 

VI.  Haisborou'gh,  general  plan 106 

VII.  Upper  part  of  English  light-house  tower 108 

VIII.  Ventilating  window  for  light-house  tower 110 

IX.  Souter  Point,  chart  of  vicinity  of 120 

X.  Souter  Point,  plan  and  details  of  low  light-room  at 122 

XI.  Sonter  Point,  plan  of  machine-room 122 

XII.  Souter  Point,  general  plan 124 

XIII.  Souter  point,  ground-plan 124 

XIV.  Souter  Point,  section  of  lantern,  lens,  and  low  light-room 126 

XV.  Souter  Point,  east  elevation 126 

XVI.  Coquet  Island,  chart  of  vicinity  of 128 

XVII.  The  Longstoue  light-house 130 

XVIII.  The  Eddystone  light-house 136 

XIX.  The  Wolf  light-house 140 

XX.  Land's  End,  chart  of  vicinity  of 142 

XXI.  Comparative  sections  of  rock  light-houses 144 

XXII.  Holmes's  fog-horn  apparatus 146 

XXIII.  South  Stack  fog  or  "  occasional "  light 156 

XXIV.  Howth  Baily  gas  light-house 158 

XXV.  Howth  Baily  gas  light-house 160 

XXVI.  Wicklow  Head  gas  light-house 162 

XXVII.  One-hundred-and-eight-jet  burner 164 

XXVIII.  Twenty-eight-jet  burner „ 168 

XXIX.  Triform  burners 172 

XXX.  Triform  lenses 174 

XXXI.  Swedish  light-ship 204 

XXXII.  Revolving  catadioptric  apparatus  for  light-ships 206 

XXXIII.  Burners  of  French  light-house  lamps 208 

XXXIV.  Interior  adjustments  of  level  in  mineral-oil  light-house  lamps 21'> 

XXXV.  Exterior  adjustments  of  level  in  mineral-oil  light-house  lamps 212 

XXXVI.  Mineral-oil  lamp  of  1845,  Lepaute's  gas-burner,  Doty  lamp 214 

XXXVII.  La  He ve,  elevation  and  general  plan 220 

XXXVIII.  La  Heve,  ground  plan  of  machine-room . , 226 

XXXIX.  La  Heve,  section  of  machine-room 230 

XL.  La  Heve,  front  elevation  of  magneto-electric  machine 232 

XLI.  La  Heve,  side  elevation  of  magneto-electric  machine 234 

XLII.  La  Heve,  plan  of  magneto-electric  machine ......  238 

XLIII.  La  Heve,  details  of  magneto-electric  machine 240 


6  ILLUSTRATIONS. 

Page. 

XLIV.  La  Heve,  switches 242 

XLV.  La  Heve,  regulators 246 

XL VI.  Lanterns  and  lenses  for  electric  and  oil  lights  at  Cape  Grisuez ....  248 

XLVII.  Submarine  foundation  for  harbor  light-houses 250 

XLVIII.  Lens  for  electric  light 254 

XLIX.  Iron  tower  for  fourth-order  light 256 

L.  Austrian  fog-trumpet 260 

FIGURES. 
No. 

1.  Roman  pharos  in  Dover  Castle 73 

2.  Douglass  gas-burner 79 

3.  Five-gallon  oil-can 91 

4.  Chimney-gauge 90 

5.  Buoy-finder  at  Yarmouth 102 

6.  Bilge-keels  of  light-ships 104 

7.  Red  cut,  Spurn  Point 116 

8.  Fastening  for  red  panes,  Whitby 119 

9.  Lamp-guard ' 119 

10.  General  view  of  establishment  at  Souter  Point .  120 

11.  Lens  and  lanterns,  Souter  Point 124 

12.  Low  light-room,  Coquet  Island 128 

13.  Filling  oil-butts  at  Saint  Catherine's 134 

14.  Red  light,  Plymouth  Breakwater 138 

15.  Rundlestone  bell-buoy,  off  Land's  End 145 

16.  Three- wick  lamp  at  Holyhead : .  „ 150 

17.  English  and  American  lanterns 154 

18.  Faraday's  wind-guard,  North  Stack 155 

19.  Diagram  illustrating  revolving  intermittent  gas-lights 163 

20.  Stevenson's  holophone,  vertical  section .  180 

21.  Stevenson's  holophone,  front  elevation 180 

22.  Mineral-oil  test,  (areometer) 188 

23.  Mineral-oil  test,  (flashing  point) 188 

24.  Sautter's  lantern  for  electric  light 207 

25.  La  Heve,  plan  of  electric  light-room 222 

26.  La  Heve,  vertical  section  of  electric  light  -room 223 

27.  La  Heve,  lens  for  electric  light , 224 

28.  Swedish  light-house,  details 257 

29.  Swedish  light-house,  details 257 

30.  Osnaghi's  reflector  for  flashing  light 262 

31.  Osnaghi's  reflector  for  fixed  light 265 


IN  THE  SENATE  OF  THE  UNITED  STATES, 

March  30,  1874. 

Resolved,  That  the  Secretary  of  the  Treasury  be  directed  to  transmit, 
for  the  information  of  the  Senate,  the  report  of  Major  George  H.  Elliot  of 
his  inspection  of  European  light-house  establishments. 
Attest: 

GEO.  C.  GORHAM,  Secretary. 

TREASURY  DEPARTMENT, 

Washington,  D.  C.,  April  23,  1874. 

SIR:  I  have  the  honor  to  transmit  copy  of  a  letter  from  Professor 
Joseph  Henry,  Chairman  of  the  Light-House  Board,  dated  the  22d  in- 
stant, covering  the  report  of  Major  George  H.  Elliot,  Engineer  Secretary 
of  the  Light-House  Board,  of  his  tour  of  inspection  of  the  light-house 
establishments  of  Europe,  submitted  in  response  to  the  resolution  of 
March  30,  (United  States  Senate,)  directing  the  Secretary  of  the  Treas- 
ury to  transmit  said  report  for  the  information  of  the  Senate. 
I  am,  very  respectfully, 

WM.  A.  RICHARDSON,  Secretary. 
Hon.  M.  H.  CARPENTER, 

President  United  States  Senate  pro  tern. 

TREASURY  DEPARTMENT, 
OFFICE  OF  THE  LIGHT-HOUSE  BOARD, 

Washington,  April  21,  1874. 

SIR:  In  compliance  with  Department  letter  of  the  1st  instant,  trans- 
mitting copy  of  the  resolution  of  the  Senate  of  the  United  States,  direct- 
ing that  "the  report  of  Major  George  H.  Elliot  of  his  inspection  of  Euro 
pean  light-house  establishments"  be  forwarded  to  that  body,  I  have  the 
honor  to  enclose  Major  Elliot's  report,  as  directed. 
Very  respectfully, 

JOSEPH  HENRY,  Chairman. 
Hon.  W.  A.  RICHARDSON, 

Secretary  of  the  Treasury. 

IN  THE  SENATE  OF  THE  UNITED  STATES, 

June  2,  1874. 

Resolved,  That  the  report  of  Major  George  H.  Elliot  of  a  tour  of  inspec- 
tion of  European  light-house  systems  be  printed,  and  that  one  thousand 
additional  copies  be  printed  for  the  use  of  the  Treasury  Department. 
Attest : 

GEORGE  C.  GORHAM,  Secretary. 


TREASURY  DEPARTMENT, 
OFFICE  OF  THE  LIGHT-HOUSE  BOARD, 

Washington,  May  25,  1874. 

SIR  :'  I  beg  leave  to  call  your  attention  to  a  report  presented  to  the 
Senate  of  tbe  United  States,  by  the  honorable  the  Secretary  of  the 
Treasury,  from  the  Light-House  Board,  by  Major  Elliot,  of  the  Engineer 
Corps. 

In  the  year  1872  the  head  of  the  light-house  system  in  Great  Britain 
sent  a  commission  to  this  country  to  examine  and  report  upon  the  fog- 
signals  which  had  been  adopted  by  the  Light-House  Establishment  of  the 
United  States,  and  in  return  for  the  courtesy  they  received  they  invited 
the  Light-House  Board  to  send  an  agent,  who  would  receive  facilities 
for  obtaining  a  knowledge  of  the  later  improvements  in  regard  to  aids 
to  navigation  which  had  been  adopted  in  Great  Britain. 

In  accordance  with  this  invitation,  the  Light-House  Board  sent  Major 
Elliot,  its  engineer-secretary,  to  obtain  the  desired  information. 

The  report  now  before  the  Senate  contains  a  full  account  of  all  the 
latest  improvements  in  regard  to  aids  to  navigation  both  in  England 
and  in  France.  It  therefore  consists  of  matter  of  great  value  to  the 
light-house  service,  and  I  beg  leave  to  request  that  you  will  advocate 
the  resolution  now  before  the  Committee  on  Printing. 

The  document  will  not  only  be  required  for  immediate  use  by  the  offi- 
cers of  the  Board  in  this  city,  and  also  by  those  in  the  various  districts, 
but  will  be  of  continued  use  for  years  to  come. 

I  have  the  honor  to  be,  very  truly,  your  obedient  servant, 

JOSEPH  HENEY, 

Chairman. 
Hon.  H.  B.  ANTHONY, 

United  States  Senate. 


EXTRACT  FROM  THE  REPORT  OF  THE  LIGHT-HOUSE  BOARD  TO  THE 
SECRETARY  OF  THE  TREASURY  FOR  THE  FISCAL  YEAR  ENDING  30iH 
JUNE,  1873. 

The  Light-House  Board,  during  the  past  year,  desirous  of  acquainting 
itself  minutely  with  any  improvements  which  of  late  years  may  have 
been  introduced  into  the  light-house  service  in  Europe,  obtained  the 
sanction  of  the  honorable  the  Secretary  of  the  Treasury  to  commission 
Major  Elliot,  of  the  Corps  of  Engineers  of  the  Army,  and  engineer- 
secretary  of  the  Board,  to  visit  Europe  and  report  upon  everything 
which  he  might  observe  relative  to  light-house  apparatus  and  the  man- 
agement of  light-house  systems.  He  has  lately  returned,  after  having 
gathered  information  which  will  prove  of  importance  in  its  application 
in  our  country,  as  will  be  evident  from  his  preliminary  report. 

Major  Elliot  was  everywhere  received  with  marked  cordiality,  and 
every  facility  was  given  him  to  inspect  the  various  coasts  and  systems 
of  administration,  of  which  full  information  was  furnished  him,  together 
with  the  drawings  and  models  necessary  for  a  perfect  acquaintance  with 
the  latest  improvements  which  have  been  adopted  in  Great  Britain  and 
on  the  continent. 

The  special  thanks  of  the  Board  are  due  to  His  Eoyal  Highness  the 
Duke  of  Edinburgh,  the  master ;  to  Sir  Frederick  Arrow,  the  Deputy 
Master,  and  the  Elder  Brethren  of  Trinity  House,  for  the  warmth  of 
their  reception  and  the  marked  distinction  they  conferred  upon  him  as 
the  representative  of  the  Board  ;  and  to  M.  Leouce  Reynaud,  Inspector- 
general  of  the  Corps  des  Ponts  et  Chaussees  and  Director  of  the  French 
light-house  service,  for  his  efforts  to  make  the  visit  of  Major  Elliot 
profitable  to  his  country  and  agreeable  to  himself. 


"  TREASURY  DEPARTMENT, 
"  OFFICE  OF  THE  LIGHT-HOUSE  BOARD, 

"  Washington,  September  17,  1873. 
"  Professor  JOSEPH  HENRY,  L.  L.  D.,  Chairman  : 

u  I  have  the  honor  to  make  a  preliminary  report  of  my  journey  of  in- 
spection of  the  light-house  establishments  of  Europe,  which  I  have  made 
by  direction  of  the  Board,  with  the  approval  of  the  honorable  the  Secre- 
tary of  the  Treasury,  and  from  which  I  returned  a  few  days  since. 

"  1  sailed  on  the  30th  of  April,  and,  after  a  pleasant  voyage,  reached 
Liverpool  on  the  10th  of  May,  observing  en  route  the  light-houses  on  the 
Irish  coast,  and  the  light-ships  and  buoys  on  the  approaches  to  Liver- 
pool. 

"  On  the  13th  of  May  I  arrived  at  London,  and  was  cordially  received 
by  Sir  Frederick  Arrow,  the  Deputy  Master,  and  the  Elder  Brethren  of 
the  Trinity  House,  which  has  charge  of  the  lights  of  England  and  a  su- 
pervisory control  over  those  of  Scotland  and  Ireland.  The  Trinity  House 
kindly  ottered  me  an  opportunity  of  making  a  tour  of  inspection  of  t!;<v 
light-houses,  &c.,  on  the  coasts  of  England  in  the  steamers  which  were 
about  to  take  the  annual  supplies,  and  at  the  first  session  after  my  ai- 


10  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

rival  a  delegation  of  the  elder  brethren  was  appointed  to  accompany 
me. 

u  I  remained  in  London  some  weeks  to  take  advantage  of  this  oppor- 
tunity, and  in  the  mean  while  my  time  was  occupied  in  inspecting  the 
depots,  lamp-shops,  photometric  test-rooms,  &c.,  belonging  to  the  Trin- 
ity House  $  also  plans  of  light-houses,  lenses,  and  other  optical  appa- 
ratus used  on  the  coasts  of  Great  Britain. 

"  In  company  with  Professor  Tyndall,  the  scientific  adviser,  some  of  the 
Elder  Brethren  and  the  engineer  of  the  Trinity  House,  I  visited  Dover 
to  attend  the  inauguration  of  fog-signal  experiments,  which,  under  Pro- 
fessor Tyndall's  direction,  are  now  being  carried  on  at  an  experimental 
station  on  the  cliffs  near  the  great  electric  lights  of  South  Foreland.  The 
light-house  authorities  of  Great  Britain  are  fully  alive  to  the  necessity 
for  powerful  fog-signals,  and  are  anxiously  seeking  to  find  the  best  ma- 
chine, not  only  to  inform  the  mariner  enveloped  in  fog  of  his  approach 
to  the  coast,  but,  by  distinguishing  characteristics  of  sound,  to  indicate 
to  him  on  what  part  of  the  coast  he  is.  The  Board  will  remember  that 
Sir  Frederick  Arrow  and  Captain  Webb,  of  the  Elder  Brethren,  visited 
the  United  States  during  the  summer  of  last  year  to  be  present  at  some 
of  our  experiments  with  the  steam-whistle,  the  horn,  and  the  siren  at 
Portland  Harbor.  I  think  the  Board  has  been  impressed  that  on  coasts 
where  fog  is  habitual,  as  those  of  New  England,  California,  and  some  of 
the  great  lakes,  fog-signals  are  fully  as  important  as  lights,  and  the 
English  seem  to  be  approaching  a  similar  conclusion. 

"Professor  Tyndall  told  me  that  he  intends  to  make  an  exhaustive 
series  of  experiments  with  all  fog-signals  now  in  use,  to  determine  the 
best.  Both  he  and  the  Elder  Brethren  are  especially  pleased  at  the 
action  of  our  Board  in  sending  an  American  siren  for  use  in  the  Dover 
experiments.  In  these  experiments  the  signals  are  observed  from  sev- 
eral vessels  cruising  in  the  Straits  of  Dover,  at  different  distances  from 
the  fog-signal  station  and  under  varying  conditions  of  wind  and  weather. 
The  signals  tested  when  I  was  at  Dover  were  a  steam-whistle,  an  air- 
whistle,  and  a  trumpet,  very  much  like  the  American  invention  of  Da- 
boll,  but  patented  by  Professor  Holmes,  and  in  use  at  several  English 
light-stations,  The  experimenters  have  since  included  a  cannon  and  our 
own  siren.  The  experiments  are  not  yet  concluded,  and  Sir  Frederick 
kindly  promised  to  inform  me  of  the  results. 

"The  delay  in  London  gave  me  an  opportunity  of  examining  the  lamps 
invented  by  Mr.  Douglass,  the  distinguished  engineer  of  Trinity  House, 
which  present  improvements  of  the  greatest  importance  as  regards  both 
the  British  lights  and  those  of  other  countries.  Not  only  is  the  bril- 
liancy of  the  flame  very  much  increased  by  ingenious  methods  of  pro- 
moting combustion,  but  the  consumption  of  oil  is  actually  decreased. 
In  British  light-houses  and  on  the  continent  colza-oil  is  generally  used, 
though,  for  the  sake  of  economy,  mineral  oil  is  being  rapidly  substituted 
for  it,  and  the  French  government  has  made  an  order  for  a  general  change 
to  mineral  oil  in  all  the  light  houses  of  the  republic. 

"When  the  Trinity  House  tender  had  been  made  ready,  I  embarked 
with  two  of  the  Elder  Brethren  (Admiral  Collinsou,  C.  B.,  and  Captain 
Weller)  to  inspect  the  British  lights  on  the  shore  of  the  North  Sea,  and 
visited  nearly  every  one  on  the  coast  from  the  mouth  of  the  Thames  to 
the  Tweed,  (the  boundary  of  Scotland,)  including  the  gas-light  at  Hais- 
borough  and  a  new  electric  light  at  Souter  Point  below  the  river  Tyne. 
At  Haisbprough  the  gas-light  was  established  for  experimental  com 
parisou  with  an  oil-light  a  few  hundred  yards  from  it,  there  being  two 
towers,  as  at  Cape  Ann  on  the  coast  of  Massachusetts.  At  Souter  Point 
the  electric  light  is  necessary,  because  the  coast  near  the  Tyne  is  euvel- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  11 

oped  by  a  dense  volume  of  smoke,  produced  by  the  immense  number  of 
manufactories  on  the  river  between  Shields  and  Newcastle. 

"  I  had  excellent  opportunities  for  testing  the  different  varieties  of 
lights  in  all  kinds  of  weather,  and  particularly  the  gas  and  electric 
lights  ill  fog.  I  was  especially  shown  the  system  of  marking  the  posi- 
tions of  rocks  and  shoals  by  means  of  what  Trinity  House  calls  "  red 
cuts,"  i.  e.  by  covering  proper  sections  of  the  dioptric  apparatus  with 
red  glass  screens;  and  at  different  places  on  the  northeast  coast  of  En- 
gland I  made  several  boat-excursions  at  night  to  test  the  utility  of  the 
system. 

"After  my  return  from  the  inspection  of  the  northeast  coast  I  embarked 
with  Captain  Webb,  of  the  Elder  Brethren,  at  Portsmouth,  and  in- 
spected the  light-houses  on  the  Isle  of  Wight  and  the  southern  coast, 
and  passed  around  Land's  End  as  far  as  St.  Ives,  on  the  west  coast  of 
Cornwall,  visiting  the  celebrated  light-house  on  the  Wolf  Rock,  off 
Land's  End,  which  is  the  most  recent  and  difficult  of  all  the  English 
examples  of  light-house  engineering.  I  regretted  that  I  could  not  land 
at  the  Eddystone  light-house,  but  the  sea,  although  usually  not  so 
dangerous  as  at  the  Wolf,  was  too  heavy  when  I  passed  it  to  make  a 
landing  practicable. 

"  Besides  the  light-houses  on  the  coast,  I  particularly  observed  the  light- 
ships and  the  system  of  buoyage ;  and  I  will  here  mention  that  the  En- 
glish use  revolving  apparatus  in  their  light-ships  in  many  cases,  and  they 
are  found  much  more  useful  than  fixed  lights.  I  would  recommend  to 
the  immediate  consideration  of  the  Board  the  propriety  of  distinguish- 
ing in  this  way  some  of  our  numerous  light-ships  off  the  coast  of  Massa- 
chusetts and  in  Long  Island  Sound. 

"  The  English  also  find  no  difficulty  in  using  fog-signals  operated  by 
hot-air  engines  in  their  light-ships,  and  I  saw  several,  in  one  case  hear- 
ing the  signal  distinctly  at  a  distance  of  eight  miles. 

"From  England  I  went  to  France,  and  had  conference  with  M. 
Keynaud,  VInspecteur  General  des  Fonts  et  Chaussees,  and  director  of  the 
French  light-house  service,  and  M.  Allard,  the  chief  engineer,  who 
is  in  charge  of  the  office  of  the  Commission  des  Phares  ;  also  with  the 
three  lens-manufacturers  of  Paris. 

"  I  was  much  interested  in  seeing  our  own  optical  apparatus  in  all  stages 
of  its  manufacture  ;  in  learning  the  modes  adopted  by  French  engineers 
of  testing  the  lenses,  burners,  and  mineral  oil ;  and  in  examining  the 
most  complete  depot  des  pliares  in  the  world,  where  are  shown  examples 
of  all  stages  in  the  progress  of  the  science  of  light-house  illumination, 
from  the  first  efforts  of  FRESNEL,  inventor  of  the  system  which  bears  his 
name,  to  the  latest  improvement  of  the  present  time. 

"I  visited  the  lights  at  the  mouth  of  the  Seine,  and  the  double  electric 
lights  of  La  Heve  at  Sainte  Adresse,  near  Havre. 

"I  afterward  proceeded  to  Vienna  and  examined  the  light-house  appa- 
ratus at  the  industrial  exhibition,  consisting  of  models,  drawings,  and 
photographs  of  light-houses  from  different  countries,  including  our  own 
A  package  of  these,  which  I  made  up  a  short  time  before  I  went  to  Eu- 
rope, I  was  glad  to  learn,  on  my  return,  obtained  a  diploma  of  honor. 

"After  returning  from  Vienna  I  visited  several  light-houses  on  the 
coast  of  Wales,  including  two  very  interesting  ones,  that  at  Holyhead 
and  one  at  the  "  South  Stack." 

"The  first-named,  a  new  one,  though  quite  ready,  was  not  lighted  until 
some  days  after  my  inspection ;  it  combined  all  the  latest  improvements 
of  the  English  in  regard  to  lens,  lamps,  and  lantern. 

"At  South  Stack  is  a  light  which  is  lowered  down  the  cliff  in  foggy 


12  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

weather  when  the  light  is  obscured  by  fog  and  it  is  clear  below,  a  plan 
which  I  had  before  thought  of  as  applicable  to  our  lights  on  the  elevated 
cliffs  of  the  Pacific  coast. 

u  I  also  visited  Ireland  and  Scotland,  the  former  by  special  invitation 
from  the  Board  of  Commissioners  of  Irish  Lights,  and  I  had  an  excellent 
opportunity  of  seeing  two  of  the  light-houses  (Howth  Baily  and  Wick- 
low  Head)"  where  the  illumiuant  used  is  gas,  of  which  Professor  Tyn- 
dall  when  in  the  United  States,  expressed  so  favorable  an  opinion  and 
which  has  been  applied  only  by  the  Irish  Board,  except  in  the  case  I 
have  mentioned,  viz,  the  experimental  light  at  Haisborough,  on  the  east 
coast  of  England. 

"  These  gas-lamps  can  be  increased  in  an  instant,  when  the  weather 
becomes  thick  or  foggy,  from  twenty-eight  to  forty- eight,  sixty-eight,  or 
eighty-eight,  even  to  one  hundred  and  eight  jets  for  dense  fog,  and  the 
inventor,  Mr.  Wigham,  of  Dublin,  exhibited  to  me  apparatus  for  pro- 
ducing a  light  from  three  hundred  and  twenty-four  jets  in  the  same  lens 
apparatus. 

"At  Edinburgh  I  visited  the  Board  of  Commissioners  of  Scottish  Lights, 
and  had  an  interesting  and  instructive  interview  with  Mr.  Thomas  Ste- 
venson, engineer  of  the  Board  and  a  member  of  the  family  of  celebrated 
Scottish  engineers. 

ul  also  visited  the  very  extensive  manufactory  of  light-house  lenses  of 
Chance  Brothers  &  Company,  near  Birmingham,  who  are  the  furnishers 
or  light-house  apparatus  to  the  Trinity  House,  and  who  also  supply  in 
a  large  degree  the  Irish  and  Scottish  Boards,  as  well  as  India,  China, 
and  South  America.  Chance  Brothers  claim  that  their  optical  appa- 
ratus is  superior  to  the  French,  and  they  certainly  have  a  great  advan- 
tage in  having  for  the  constant  supervision  of  their  work  a  gentleman 
of  high  scientific  attainments. 

. "  I  carried  with  me  a  special  letter  from  the  honorable  the  Secretary  of 
State  to  the  ministers  and  consuls  of  the  United  States  in  Europe,  and 
I  received  every  facility  and  courtesy  from  them  and  from  the  officials 
of  the  countries  which  I  visited. 

"I  have  full  notes  of  my  inspection,  and  at  an  early  day  shall  have  the 
honor  to  present  to  you  a  detailed  report  of  what  I  saw  differing  from 
our  own  system. 

"  In  closing  this  preliminary  report,  I  will  say  that  the  great  questions 
which  are  occupying  the  attention  of  the  light-house   authorities  of 
Europe,  and  in  which  the  different  establishments  are  in  competition 
with  each  other,  are  : 
"  What  is  the  best  illuminant  f  and 

"What  is  the  best  means  for  producing  the  most  perfect  combustion  ? 
"I  will  only  add  that  while  the  British  and  French  systems  are  neces- 
sarily very  much  like  our  own,  I  saw  many  details  of  construction  and 
administration  which  we  can  adopt  to  advantage,  (and  which  I  shall 
exhibit  in  my  detailed  report,)  while  there  are  many  in  which  we  excel. 
Our  shore  fog-signals,  particularly,  are  vastly  superior  both  in  number 
and  power.  They  are  in  advance  of  us  in  using  both  the  gas  and  elec- 
tric lights  in  positions  of  special  importance,  in  the  use  of  azimuthal 
condensing  prisms  for  certain  localities ;  in  the  character  of  their  lamps; 
in  the  use  of  fog  signals  in  light-ships  ;  in  their  light-ships  with  revolv- 
ing lights,  and,  more  than  all,  in  the  character  of  their  keepers,  who  are 
in  service  during  good  behavior  until  death  or  superannuation,  who  are 
promoted  for  merit,  and  whose  lives  are  insured  by  the  government  for 
the  benefit  of  their  families. 

UI  am  much  indebted  to  Mr.  Paul  J.  Pelz,  chief  draughtsman  to  the 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  13 

Board,  who  accompanied  me  by  its  permission  and  with  the  approval 
of  the  honorable  the  Secretary  of  the  Treasury,  as  my  secretary,  and 
who  has  made  many  sketches  for  the  illustration  of  my  report,  and  who 
has,  in  other  ways,  been  of  much  assistance  to  me  in  the  execution  of 
the  duty  assigned  me. 

"Very  respectfully, 

"GEOKGE  H.  ELLIOT, 
"Major  of  Engineers  U.  S.  A.,  Engineer- Secretary." 


REPORT. 


OUTWARD  VOYAGKE. 

As  stated  in  the  preliminary  report  of  my  journey  of   Date  of  sailing. 
inspection   of  the  European  light-house  establishments,  I 
sailed  from  New  York  in  the  steamship  Cuba,  of  the  Canard 
line,  on  the  30th  of  April,  1873. 

During  the  voyage  I  had  many  interesting  conversations    conversation 
with  the  commander,  Captain  McCauley,  in  regard  to  the  McCauiey  apcon" 
lights  of  the  United  States,  France,  and  England.     In  ref-  SniightsAmeri' 
erence  to  our  own  lights  he  stated  that  they  were  in  general 
satisfactory  to  mariners,  and  had  been  of  great  service  to 
him  011  many  occasions,  during  his  long  service  in  the 
Cunard  Company,  especially  in  running  between  Boston 
and  New  York  and  between  Halifax  and  Boston. 

With  respect  to  brilliancy,  the  English  and  American  Brilliancy  of 
lights  are,  in  his  opinion,  about  equal,  but  those  of  thefr^ceh,randaEnl 
French  he  considers  superior  to  either. 

He  said  of  the  electric  lights,  of  which  the  English  and    Electric  lights 
French  have  several,  that  they  penetrated  fog  much  more1*6 
successfully  than  the  common  oil-light,  and  aids  to  naviga- 
tion in  fog  are,  in  his  opinion,  vastly  more  important  than 
for  fair  weather. 

Our  fog-signals  he  praised  highly,  saying  that  the  steam-    Fog-signals  of 
whistle  at  Cape  Ann  and  the  siren  at  Sandy  Hook  had  fJ  marfuers"  a 
often  been  of  great  service  to  him,  and  he  confidently  relied 
on  hearing  them  at  distances  of  from  six  to  eight  miles.     He 


thought  it  would  be  much  to  the  interest  of  commerce  if  the  gh 


British  government  would  place  similar  signals  at  impor- 
tant points,  as  the  channel  approaches  to  Great  Britain 
were  nearly  as  much  subject  to  fogs  as  is  our  eastern  coast. 

Our  Nantucket  Shoals  he  considered  to  be  badly  lighted,    insufficient 
and  called  my  attention  to  the  fact  that  on  the  coasts  of  ISetlholi^11 
Great  Britain,  in  similar  localities,  light-ships  are  placed 
at  distances  of  ten  to  twelve  miles  apart  ;  such  I  found 
afterward  to  be  the  case.     He  thought  a  light-ship  should  Light-ship  need- 
be  placed  off  the  Eose  and  Crown  Shoal,  (which  is  due  east  Sown  sho2i.aud 
from  Saukaty  Head,  on  the  Island  of  Nantucket,)  so  that  a 
vessel  could  take  a  course  to  it  from  the  Highlands  (Cape 
Cod)  light,  and  thence  to  the  Nantucket  New  South  Shoals 
light-ship,  which  he  thought  should  be  moved  farther  out. 

N:  HI:.  —The  inoro  important  points  to  which  attention  is  called  in 
this  report  are  noted  iri  the  concluding  pages  267  to  272, 


16  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Meeting  with     On  the  fifth  night  out  from  New  York  (the  night  of  the 

steamer  on  ?STew-  ,,,„-..-»  i  •  IT        r*       * 

Banks  4th  of  May)  we  met  a  steamship  on  the  Banks  off  New- 


in  a  thick  fog.     founclland?  but  tnere  being  at  the  time  one  of  those  dense 
fogs  prevalent  at  some  seasons  of  the  year  in  that  part 
of  the  Atlantic,  we  did  not  see  her,  and  only  7cnew  of  her 
proximity  by  the  sound  of  her  whistle,  a  fact  which  impressed 
importance  of  me  with  the  importance  of  powerful  fog-signals   on  the 

t°rgaSngsDatsi  antic  steam  ships  plying  between  America  and  Europe  on  this 

much-frequented  track.* 
Danger  of  coi-     I11  addition  to  the  large  number  of  steamships  the  num- 

Sdl°duringVges!~  ber  of  sailing-  vessels  is  very  great,  and  the  tales  of  narrow 
escapes  from  collision,  especially  with  fishermen  anchored 
on  the  Banks,  which  one  hears  while  (enveloped  in  dense 
fog)  he  is  steaming  along  at  a  high  rate  of  speed,  very  much 
impair  the  confidence  which  is  naturally  inspired  by  vessels 
like  those  of  the  Cunard  line  and  commanders  like  Captain 
McCauley  ;  for  it  is  evident  that  want  of  efficient  fog-signals 
cannot  be  compensated  for  by  strength  of  ship  or  skill  of 
i  n  s  nfficiency  officers.  The  whistles  in  use  are,  I  am  told,  frequently  in- 

ot  whistles  in  use  J 

on  steamers.       sufficient  in  power,  and,  being  placed  abaft  the  foresails  and 
in  front  of  the  great  smoke-pipes,  are  in  such  positions  that 
the  sound-shadows  often   cover  the  precise  directions   in 
which  it  is  most  essential  the  warning  should  be  conveyed. 
Position   and     I  am  of  the  opinion  that  not  only  the  position  but  the  kind 
shouhf  sife  of  fog-  signals  to  be  used  in  transatlantic  steamers  should 


be  regulated  by  a  joint  commission  of  the  governments  in- 
terested, and  that,  before  deciding  these  questions,  not  only 
the  whistle,  but  the  Daboll  trumpet  and  the  siren  which  we 
use  at  our  fog-signal  stations  on  shore,  as  well  as  the  Aus- 
trian fog  trumpet,  (shown  in  Plate  L,)  should  be  considered. 
As  the  power  necessary  to  operate  these  signals  is  on 
these  steamships  always  at  hand,  it  is  not,  as  in  the  light- 
house service,  a  question  of  cost  of  maintenance,  but  the 
questions  to  be  decided  on  are  : 
Questions  to  be  First.  What  is  the  most  efficient  instrument  for  the  pur- 

detcrmined. 


Second.  What  is  the  most  advantageous  position  practica- 

ble for  it? 

he?tupositio0nnfor     Ttlis  Position?  it  is  evident,  must  be  one  in  no  way  inter- 
steamer's  fog-sig-fering  with  the  management  of  the  sails  and  rigging,  and 

where  no  danger  exists  of  the  signal  being  carried  away  by 

the  sea. 

*  From  information  derived  from,  my  friend,  Mr.  George  W.  Blunt, 
of  New  York,  and  from  other  sources,  it  appears  that  on  an  average  from 
eight  to  ten  steamers  cross  the  Banks  every  day  going  from  America 
to  Europe  and  vice  versa. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  17 

The  question  of  ship-lights  should  also  be  determined  by  ship  lights. 
the  same  commission,  and  I  have  no  doubt  the  magneto- 
electric  light,  which  I  believe  has  been  spoken  of  before  in 
this  connection,  and  which  is  fully  described  in  this  report, 
will  have  favorable  consideration,  since  the  steam-power 
necessary  for  operating  the  magnetic  machines  is  constantly 
available. 

On  the  morning  of  Friday,  the  9th  of  May,  we  made  rhe 
southwesterly  point  of  Ireland,  and  had  a  good  opportunity 
'of  seeing  the  important  light-house  on  Fastnet  Eock,  off   Fastnet  iiock 
Cape  Clear.    This  tower,  having  nearly  vertical  sides,  which  u 
spread  with  a  curve  near  the  base,  is  92  feet  high,  and, 
together  with  the  appendages,  presents  a  very  picturesque 
appearance,  being  surrounded  by  a  high  retaining-wall, 
necessary,  apparently,  for  the  formation  of  a  platform  large 
enough  for  the  establishment. 

The  lantern  has  the  vertical  sash-bars  introduced  into 
our  service  from  the  French.  A  broad  band  of  red  con- 
trasts strongly  with  the  color  of  the  main  body  of  the  tower, 
which  is  built  of  iron. 

As  the  Cuba  steamed  along  the  south  coast  of  Ireland, 
and  from  two  to  four  miles  distant  from  the  shore,  a  good 
view  of  the  neat  light-stations  was  afforded. 

A  very  interesting  one  was  the  Old  Head  of  Kinsale  with    oia   Head  of 

Kinsale  light. 

its  tall  tower,  on  which  two  red  bands  distinguished  it  as  a 
day-mark. 

Each  of  the  stations  appears  to  have  capacious  grounds 
walled  in  with  stone,  and  all  are  neatly  whitewashed.    The 
buildings  connected  with  light-houses  are  generally  of  one 
story,  covering  a  large  area.     We  passed  Bally  cottin  light,  .  Bali. v  cot  tin 
which  stands  195  feet  above  the  sea,  and  when  we  stopped  lf 
at  Queenstown  to  deliver  the  mails,  we  saw  on  the  eastern 
head  of  the  harbor  the  handsome  light  at  Point  Koche.        u^1  n  *  Eoclie 

Off  the  mouth  of  this  harbor  is  an  extensive  shoal,  the 
upper  end  marked  by  a  bell-boat,  and  the  lower  by  a  can-    Beii-boat. 
buoy,  on  which  the  word  "  Danger  "  was  painted  in  white 
letters. 

A  few  hours  after  leaving  Queenstowa.  we  passed  theH^skar  Rock 
light-house  on  Tuskar  Eock,  at  the  entrance  of  St.  George's 
Channel,  evidently  an  important  station.  The  tower,  to 
which  is  attached  the  double  dwelling  for  the  keepers,  is 
100  feet  high.  Tuskar  Eock  is  several  miles  from  shore,  in 
the  great  highway  to  Liverpool,  so  that  vessels  entering  or 
leaving  St.  George's  Channel  pass  quite  near  it. 

It  was  on  this  rock  that  the  Cuuard  steamship  Tripoli 
struck  a  short  time  ago,  and  it  is  evident  that  the  powerful 
S.  Ex.  54 2 


18  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

fog-signal  that  the  English  government  proposes  to  place  at 
this  point  is  much  needed. 

Arrival  at  the  On  the  morning  of  the  10th  we  arrived  at  the  mouth  of 
the  Mersey,  and,  after  waiting  an  hour  or  more  for  sufficient 
tide  to  take  us  over  the  bar,  we  proceeded  up  the  river  to 
Liverpool. 

Beii-buoy  on  On  the  bar  we  passed  a  large  bell-buoy,  shaped  like  our 
nun-buoys,  above  the  water-line,  except  that  it  rested  on  a 
large  bearing-surface,  projecting  a  foot  or  more  beyond  its 
sides. 

The  sea  being  quite  smooth,  the  bell  was  silent,  as  is  too 
often  the  case  with  this  very  unreliable  kind  of  signal. 

Buoyage  of     The  channel  of  the  river  is  marked  by  frequent  buoys ; 
channel.  ou  the  starboard  hand  red  "  can,'7  and  on  the  port  black 

tl  nun." 

Light-ships  We  passed  several  light-ships,  some  of  which,  as  Captain 
Hgkte. revolving  McCauley  informed  me,  have  revolving  lights,  an  important 
fact  to  be  noted,  since  a  revolving  is  seen  much  farther  than 
a  fixed  light,  and,  when  light-ships  are  numerous,  as  off  the 
southeastern  Irish  coast,  in  the  approaches  to  Liverpool,  or 
on  the  shoals  off  the  coast  of  Massachusetts,  distinguishing 
characteristics  are  as  necessary  as  for  shore-lights. 

Docks,  &c.,  at     I  spent  a  day  examining  the  great  docks  at  Liverpool,  and 

Liverpool.          afc  Birkenhead,  on  the  opposite  side  of  the  river,  and  became 

much  interested  in  the  immense  walls,  the  gates  and  bridges, 

swung  by  hydraulic  power,  and  many  other  objects  which 

this  is  not  the  place  to  describe. 

TRINITY    HOUSE,  LONDON. 

visit  to  the     Soon  after  reaching  London  I  called  at  the  Trinity  House, 

Trinity  House.  °      . 

where  I  was  received  with  great  politeness  by  Sir  Frederick 
Arrow,  the  Deputy  Master,  who,  with  Captain  Webb,  of  the 
Elder  Brethren,  visited  America  during  the  summer  of  1872 
for  the  purpose  of  attending  our  fog-signal  experiments 
made  in  the  harbor  of  Portland,  in  the  State  of  Maine,  after 
which  we  had  the  pleasure  of  meeting  them  at  Washington, 
improvements      Sir  Frederick  expressed  his  gratification  at  the  attentions 
in  lamps.  ^  received  in  the  United  States,  and  after  an  interesting 

conversation  regarding  our  respective  establishments,  par- 
ticularly relating  to  our  fog-signals  and  to  the  very  great 
improvements  in  light-house  lamps  made  by  the  Trinity 
House,  (whereby  the  quantity  of  light  from  the  "  four- wick  » 
Advantage  lamp  for  large  sea-coast  light-houses  had  been  increased  22 
per  cent.,  while  the  consumption  of  oil  had  actually  been  de- 
creased more  than  19  per  cent.,  an  advantage  of  over  41  per 
cent,  in  favor  of  the  new  lamp  for  large  towers,  and  a  still 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  19 

greater  one  for  smaller  sea-coast  and  harbor  lights,)  he  said 
that  since  I  informed  him  of  my  intended  visit  to  Europe 
he  had  made  several  engagements  for  me,  including  a  din- 
ner at  the  Lord  Mayor's  on  the  21st  of  May,  in  honor  of  the 
return  of  the  Master  of  Trinity  House,  the  Duke  of  Edin- 
burgh ;  several  cruises  around  the  coast  of  England  in  the 
steam-yachts  of  the  corporation,  which  were  shortly  to  start 
on  their  annual  supply-voyages  to  the  light-stations,  and  a 
visit  to  Dover,  to  be  present  at  some  fog-signal  experiments 
to  be  undertaken  by  the  Elder  Brethren  under  direction  of 
Professor  Tyndall. 

It  was  during  this  visit  that  I  had  the  pleasure  of  meet- 
ing Mr.  Eobiu  Allen,  for  many  years  the  Secretary  of  the 
Trinity  House,  and  Mr.  Edwards,  private  secretary  of  the 
Deputy  Master,  who  accompanied  him  on  his  visit  to  the 
United  States. 

During  my  stay  in  London  I  made  frequent  visits  to  the 
Trinity  House,  and  was  very  soon  after  my  arrival  intro- 
duced to  Mr.  Douglass,  the  talented  Engineer  of  the  establish- 
ment, and  to  most  of  the  Elder  Brethren  ;  the  pleasure  was 
also  afforded  me  of  meeting  my  friend  Captain  Webb,  and 
I  was  glad  to  hear  that  it  was  with  him  that  one  of  my 
cruises  among  the  British  light-houses  was  to  be  made. 

Mr.  Douglass  showed  me  his  plans  of  some  of  the  more    PIMM  of  light- 
important   English   light-houses,  particularly  that  of  the 


Wolf  Kock,  off  Land's  End,  as  well  as  his  drawings  of 

lanterns  and  lamps.  iamrswings     °f 

It  is  noticeable  that  the  English,  in  their  lanterns,  use    Sash-bars    in 
diagonal  sash-bars  and  low  parapets,  (or  unglazed  parts,) 
differing  in  this  respect  from  the  French  and  ourselves. 

Mr.  Douglass  was,  as  I  afterward  found  the  French  and    interest  of  EU 
other  light-house  engineers  of  Europe  to  be,  especially  in-  in^ia^psTmiS 
terested  in  the  subject  of  lamps  as  well  as  that  of  material  for  Iigllt"hou8es' 
for  illumination,  these  subjects  being  considered  of  most 
importance  at  the  present  time  in  light-house  administra- 
tion. 

Within  the  last  five  or  six  years  improvements  have  been 
made  from  time  to  time  in  lenticular  apparatus,  but  they 
are  of  trifling  importance  when  contrasted  with  the  great    increase  i 
increase  of  power  and  concurrent  decrease  of  expense  of  sea-  am 
coast  lights  as  compared  with  the  system  in  use  in  Europe  ex 
a  few  years  ago,  and  with  ours  of  the  present  time. 

These  vast  ameliorations  have  been  produced  by  —  causes  Pro- 


1st.  The  introduction  of  mineral  oil  for  light-house  illumi- 


nation. 


20  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

2d.  The  improvements  in  u  burners "  for  lamps,  resulting 
from  experiments  made  to  determine  the  best  form  of  lamps  for 
burning  mineral  oil  in  light-houses,  ichich  improvements  apply 
equally  to  lamps  burning  oil  of  a  mineral,  animal,  or  vegetable 
origin. 

This  matter  will  be  more  fully  noted  when  I  come  to  describe 

photometric  the  depot  at  Blackwall.    I  was  shown  the  room  devoted  to 

at8'      photometric  experiments,  where  a  six- wick  lamp  burning 

colza-oil,  a  four-wick  lamp  for  mineral  oil,  and  small  one-wick 

lamps  of  both  the  new  and  old  styles  were  burning  for  my 

inspection. 

There  was  a  very  remarkable  difference  of  color  and  bril- 
liancy between  the  flames  of  the  improved  and  the  other 
lamps,  that  of  the  latter  being  of  a  dirty  yellowish  hue, 
while  that  of  the  former,  being  more  plentifully  supplied 
with  air,  appeared  perfectly  white,  surpassing  even  the 
excellent  gas-light  of  London. 

corporation  of  The  Corporation  of  Trinity  House,  or,  -according  to  the 
original  charter,  "  The  Master,  Wardens,  and  Assistants  of 
the  Guild,  Fraternity,  or  Brotherhood  of  the  Most  Glorious 
and  Undivided  Trinity,  and  of  St.  Clement,  in  the  parish 
of  Deptford  Strond,  in  the  county  of  Kent,"  existed  as  early 
tj>ate  of  char-  as  the  reign  of  Henry  VII,  and  was  incorporated  by  royal 
charter  during  the  reign  of  Henry  VIII. 

In  the  year  1565,  in  the  reign  of  Queen  Elizabeth,  the 

corporation  was  empowered,  by  act  of  Parliament,  "to 

preserve  ancient  sea-marks  and  to  erect  beacons,  marks, 

and  signs  of  the  sea,"  but  it  was  more  than  a  century,  i.  e., 

Date  of    first  Dot  until  1680,  before  the  corporation  constructed  or  owned 

owning    light- 

houses.  any  light-houses.  After  that  date  it  from  time  to  time  pur- 

chased the  lights  which  were  owned  by  individuals  or  by 

Entire  control  the  Crown,  and  also  erected  new  ones.  In  1836  an  act  of 
?estecPh? Trility  Parliament  vested  in  the  Trinity  House  the  entire  control 
of  the  light-houses  of  England  and  Wales,  and  gave  it  cer- 
tain powers  over  the  Irish  and  Scotch  lights. 

Light-dues.  Prior  to*  the  act  of  1836  the  charge  was  from  one-sixth  of 
a  penny  to  one  penny  per  ton  on  all  ships  at  each  time  of 
passing  a  light-house,  but  by  this  act  uniform  light-dues  of 
a  halfpenny  per  ton  were  established. 

At  Beii  Eock.  The  charge  of  one  penny  per  ton  at  Bell  Rock  light-house 
is  the  only  exception  to  this  uniform  rate.  By  further  pro- 
is]Jeaeatshipping  visions  of  the  act,  national  ships,  fishing- vessels,  and  ves- 
sels in  ballast  are  exempt  from  light-dues. 

Light-houses     It  should  be  mentioned  that  only  the  light-houses  for 

not  owned  by  the 

Trinity  House,    general  use  are  owned  by  the  Trinity  House,  harbor  and 
other  local  lights  being  constructed  and  maintained  at  the 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  ' 

expense  of  the  cities  or  localities  which  they  especially  ben- 
efit; but  the  Trinity  House  not  only  has  over  them  a  super- 
visory control  in  regard  to  their  sites  and  plans,  but  in- 
spects them  from  time  to  time,  thus  securing  their  efficiency. 

The  Elder  Brethren,  twenty-nine  in  number,  comprise  six-    The  Eider 
teen  active  members,  including  two  officers  of  the  Navy, Bl 
anct  thirteen  honorary  members,  all  of  whom  are  elected  by 
the  body  as  vacancies  occur. 

The  honorary  members  include  his  royal  highness  the   Honorary  mem- 
Prince  of  Wales,  some  of  the  ministers  to  the  Crown,  sev- bers' 
eral  members  of  the  nobility  and  of  Parliament. 

The  Duke  of  Edinburgh  is  the  present  Master,  but  the    Master  and 
Deputy  Master,  who  is  elected  by  the  Elder  Brethren  from 
their  active  list,  is  the  executive  officer. 

Out  of  the  annual  revenues  £350  are  paid  to  each  of  the    salaries. 
active  members ;  these  members  are  organized  into  commit-    Committees, 
tees,  which  meet  twice  a  week  except  when  absent  on  duty. 

The  entire  board  holds  weekly  sessions,  at  which  the  mat-  weekly  ses- 
ters  before  considered  in  committee  are  disposed  of. 

The  corporation  of  the  Trinity  House  includes  also  the    Junior  Breth- 
Juuior  Brethren,  who  are  elected  by  the  Elder  Brethren,  and 
simply  form  a  reserve  from  which  the  Elder  Brethren  add  to 
their  own  number  when  vacancies  occur. 

The  Junior  Brethren  have  no  duties. 

Since  1854  the  Trinity  House  has  been  subordinate  to  the  The  Trinity 
Board  of  Trade,  whose  president  is  one  of  the  Queen's  Min-  na°t"sto  Board  of 
isters. 

All  light-dues  collected  by  the  corporation  of  Trinity   The  mercantile- 
House  go  into  a  general  fund  called  "  the  mercantile-marine  m 
fund,"  from  which  is  paid  the  cost  of  the  maintenance  of 
the  light-house  establishment  and  of  the  erection  of  new 
lights.    This  fund  is  under  the  control  of  the  Boar<J  of  Trade, 
whose  authority  must  be  obtained  for  the  erection  of  any 
new  light-house  or  for  any  important  change  in  administra- 
tion. 

This  subordination  to  the  Board  of  Trade  extends  to  the  Light -house 
light-house  boards  of  Scotland  and  Ireland,  causing,  I  was  ia°nd  a8nd  Ireland 

,    -,  -,  ,     .  .  -.          ,  subordinate       to 

told,  much  inconvenience  and  embarrassment.  Board  of  Trade. 

Modifications  in  the  light-house  administration  of  Great    observations 

upon  the  charac- 

Britam  have  been  from  time  to  time  suggested  and  changes  ter  of  the  British 
may  be  desirable  ;  but,  judging  by  my  own  observations,  the 
English  lights,  many  more  of  which  I  saw  than  of  the  Irish  and 
Scotch,  are  certainly  managed  in  a  most  efficient  manner, 
and,  since  the  great  improvements  introduced  by  the  emi- 
nent engineer,  Mr.  Douglass,  the  English  may  fairly  be  said 


22  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

to  hate  placed  themselves  on  an  equality  with  the  French, 
who  have  so  long  led  the  world  in  the  matter  of  light-house 
illumination. 

Trinity  House.  Trinity  House  is  an  ancient  structure  on  Tower  Hill, 
opposite  the  old  Tower  of  London,  in  "  The  City."  It  has  a 
handsome  freestone  front  in  classic  style.  The  main  en- 
trance is  on  the  ground-floor  through  a  capacious  hall,  where 
are  exhibited  models  of  many  of  the  most  celebrated  light- 
houses of  England,  and  also  of  beacons  and  buoys. 

office  accomda-  Ample  accommodations  are  afforded  for  the  officers,  for 
the  Board  and  committees,  for  the  Engineer's  Department, 
and  for  the  photometric  experiments,  and,  in  addition, 
there  is  a  grand  banqueting  hall  and  salon. 

I  am  under  obligations  to  General  Schenck,  the  American 
minister  ;  to  Mr.  Moran,  the  secretary;  and  to  Captain  Earn- 
say,  United  States  Navy,  attache  of  the  legation,  for  offers 
of  assistance,  of  which  my  previous  acquaintance  with  Sir 
Frederick  Arrow  and  Captain  Webb  and  the  kindness  of 
the  Elder  Brethren  made  it  unnecessary  for  me  to  avail 
myself. 

FOGr-SIGrNAL  EXPERIMENTS  NEAR  DOVER. 

Experiments     On  the  19th  of  May  I  proceeded  to  Dover,  to  be  present 


og-signas.  aj.  ^e  commencement  of  an  extensive  series  of  fog-signal 
experiments,  to  be  undertaken  by  the  Trinity  House,  under 
the  supervision  of  their  scientific  adviser,  Professor  Tyndall. 

There  were  present  on  this  occasion,  besides  Professor 
Tyiidall,  several  of  the  Elder  Brethren,  the  Engineer  of  the 
Trinity  House,  a  representative  from  the  Board  of  Trade, 
and  the  Inspector  of  Irish  lights. 

The  experimenters  divided  themselves  into  two  parties, 
and  embarked  on  two  steam  -yachts,  for  the  purpose  of  prac- 
tically testing  the  sounds  while  afloat. 

The  limited  time  at  my  disposal  did  not  allow  me  the 
pleasure  of  accepting  an  invitation  to  join  them,  and  I  had 
only  an  opportunity  of  observing  the  machines  themselves 
at  the  experimental  station  at  South  Foreland.  This  I  did 
before  inspecting  the  South  Foreland  light-houses,  to  which 
I  at  once  proceeded. 

Disposition  of  There  were  two  sets  of  signals  used  ;  one  placed  on  the 
summit  of  the  cliff  near  the  engine-house  belonging  to  the 
light-station,  at  an  elevation  of  275  feet  above  the  sea;  the 
other  near  the  foot  of  the  cliff,  at  an  elevation  of  40  feet, 
and  near  the  bottom  of  an  old  shaft,  by  which  it  was  reached 
from  the  upper  station. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  23 

The  machines  used  were  steam-whistles,  air-whistles,  and 
fog-trumpets.    The  trumpets  and  the  air-whistles  were  con-  ^fanner  of  01> 
nected  with  two  air  chambers,  supplied  with  air  by  pumps 
driven  by  the  engine  used  for  the  electric  lights. 

An  Ericsson  engine  was  at  the  station,  but  was  not  used. 

The  steam-whistles  were  supplied  by  a  twenty  horse-power 
upright  engine. 

The  trumpets  were  shaped  like  those  used  in  our  owu  serv-    shape  and  dt- 

_  _  .       ,          ,       ,  mensions  of  sig- 

ice.    The  steam- whistles,  with  a  diameter  of  12  inches,  hadnais. 
a  height  of  14  inches,  the  space  between  the  lip  and  the 
disk  being  1J  inches.    The  air-whistles,  with  a  diameter  of 
6  inches,  were  9J  inches  high,  the  lips  being  placed  1J 
inches  from  the  disks. 

The  steam- whistles  were  blown  under  a  pressure  of  64    pressure  used, 
pounds;  the  air-trumpets  and  whistles  under  a  pressure  of 
18  pounds.    Behind  these  latter  were  reflectors  about  12  by    sound-reflect- 
15  feet,  slightly  curved  toward  the  laud. 

The  day  was  stormy,  there  being  a  high  wind  from  the 
eastward  accompanied  by  rain,  and  the  Strait  of  Dover  was 
pretty  rough,  but  on  the  whole  the  weather  was  favorable 
for  the  purpose.  The  two  parties  continued  afloat  all  day, 
and  the  signals  were  sounded  until  dark. 

On  shore,  so  near  the  signals,  and  while  inspecting  the 
light-houses,  I  could  not  determine  in  regard  to  the  qualities 
of  the  different  sounds  as  well  as  could  those  on  board  the 
yachts,  but,  so  far  as  I  could  judge,  the  air- whistles  and 
trumpets  were  decidedly  superior  to  the  steam  (12-inch) 
whistles.  The  note  of  the  latter  was  much  more  shrill  than 
that  found  by  us  to  best  serve  the  purpose  for  which  this  in- 
strument is  designed,  and  the  condensation  of  the  steam, 
and  consequent  drip  of  water*  were  so  great,  I  was  con- 
vinced, as  to  greatly  impair  the  vibration. 

The  results  of  the  trial  of  the  12-inch  steam-whistle  were    Results  less 

. .    n  . ,  .    satisfactory  than 

from  some  cause  much  less  satisfactory  than  in  our  expen-  at  Portland,  Me. 
ments  at  Portland,  and  at  our  light-stations,  the  sound  pro- 
duced being  certainly  no  louder  than  that  of  the  6-inch  air- 
whistle. 
On  the  return  of  the  experimental  parties  in  the  evening,    op  in  ions  of 

.  .  .  experimenters. 

there  was  a  general  expression  of  disappointment  in  regard 
to  all  the  signals. 
It  was  stated  that  the  yachts  ran  outside  the  limits  of  Short  distance 

««,*.,  at     which     the 

sound  at  comparatively  short  distances  ;  that  the  air  truin-  sound  failed  to 
pets  and  whistles  were  heard  much  farther  than  the  steam- re 
whistles,  while  a  gun  fired  at  Dover  Castle  was  heard  at 
much  greater  distance  than  any  of  the  signals  at  the  station. 

*  It  may  have  been  water  thrown  out  with  the  steam  in  consequence 
of  the  insufficient  height  of  the  whistle  above  the  boiler. 


24  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

The  yachts  were  out  in  the  channel  occupying  various 
positions  in  relation  to  the  wind,  and  the  signals  were  regu- 
larly sounded  according  to  a  program  me  previously  arranged. 

The  experiments,  in  which  were  afterward  included  one 
of  our  own  whistles  and  sirens,  were  to  be  continued  for 
some  months.  Following  will  be  found  a  list  of  the  printed 
decided.1011  6questions  to  be  considered  and  answered  by  the  experi- 
menters. 

"  SOUTH  FORELAND   FOG-SIGNAL  EXPERIMENTS.— QUES- 
TIONS PROPOSED    TO  BE  DETERMINED. 

u  First.  What  is  the  most  efficient  height  above  the  sea- 
surface  for  the  signals  ? 

"  Second.  What  are  the  comparative  values  of  air  and 
steam  for  sounding  whistles  and  horns  ? 

"  Third.  Which  is  the  more  efficient  instrument — whistle 
or  horn  ? 

u  Fourth.  What  is  the  proper  pressure,  having  regard  to 
efficiency  and  economy,  at  which  air  or  steam  should  be  em- 
ployed for  whistles  or  horns  ? 

"  Fifth.  What  is  the  relative  range  of  the  same  whistle  or 
horn  with  various  pressures  of  steam  or  air  ? 

"  Sixth.  What  is  the  relative  range  of  long  and  short 
blasts  from  the  same  instrument,  and  what  is  the  minimum 
duration  of  the  blasts  of  maximum  efficiency  f 

"  Seventh.  What  is  the  most  efficient  note  for  a  fog-signal? 

"  Eighth.  What  is  the  relative  range  of  the  highest  and 
lowest  notes  of  the  same  instrument  f 

"  Ninth.  What  is  the  relative  range  of  one  and  two  whis- 
tles or  horns  of  the  same  power  ? 

"  Tenth.  What  is  the  relative  range  of  the  horn  in  the  di- 
rection of  its  axis,  and  at  45°  and  90°  respectively  from  the 
direction  of  its  axis  ? 

"  Eleventh.  Is  the  horn  used  with  maximum  efficiency  by 
always  keeping  it  pointed  to  windward,  by  using  more  than 
one  horn  and  distributing  the  sound  over  the  phonic  arcs 
or  by  rotating  one  horn  ? 

"  Twelfth.  Is  any  appreciable  advantage  gained  by  using 
reflectors  in  conjunction  with  whistles  or  horns  ;  and,  if  so, 
what  shape  is  preferable  ? 

u  Thirteenth.  What  horse-power  is  required  to  sound  the 
most  efficient  signal  (whistle  or  trumpet)  for  giving  an  effect- 
ive range  (of  two  miles)  in  fog  and  against  wind  at  force  9 
of  the  Beaufort  scale  ? 

"  Fourteenth.  How  is  the  propagation  and  distribution  of 
sound  affected  by  different  atmospheric  conditions  cl " 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  25 

It  has  been  found  by  General  Duane,  of  the  Corps  of  En-    Experiments  of 

,.  General  Duaue. 

gineers  United  States  Army,  and  light-house  engineer  of 
the  New  England  coast,  in  his  experiments  made  to  de- 
termine the  best  form  of  boilers  for  steam  fog-signals,  that, 
as  the  steam  used  is  at  a  high  pressure,  and  is  drawn  off  at 
intervals,  and  there  is  a  consequent  tendency  to  foam  and 
to  throw  out  water  with  the  steam,  a  horizontal  tubular  boiler  Boilers  best  to 

i     -i  n      i>   it       •    i      •       be  used  for  foe- 

( locomotive)  with  rather  more  than  one-half  of  the  interior  signals. 
space  allowed  for  steam-room,  is  best  adapted  for  the  purpose. 

The  steam-dome  must  be  very  large  and  be  surmounted  steam-dome  ami 
by  a  steam-pipe  12  inches  in  diameter.     Both  dome  and  pipe 
were  first  made  small,  and  were  gradually  enlarged  until  no 
difficulty  with  regard  to  foaming  remained. 

The  steam  should  be  drawn  off  at  a  point  10  feet  above    DrawinS-off 

»  ,1-1  point    for    the 

the  water-level  in  the  boiler.  steam. 

The  main  points,  therefore,  to  be  observed  in  regard  to 
the  boiler j  are  to  have  plenty  of  steam-room  and  to  draw 
the  steam  from  a  point  high  above  the  water-level. 

In  regard  to  the  bell  of  the  whistle,  the  best  results  have  rormofwnistie. 
been  obtained  by  making  the  diameter  two-thirds  of  its 
length,  and  the  "  set"  of  the  bell,  i.  e.,  the  vertical  distance 
of  the  lower  edge  above  the  cup,  from  one-fourth  to  one- 
third  of  the  diameter  for  a  pressure  of  steam  of  from  50  to 
60  pounds. 

These  conditions  were  not  fulfilled  in  the  Dover  experi- 
ments at  the  time  of  my  visit,  and  I  have  no  doubt  that  this 
accounts  in  some  measure  for  the  disappointing  results  of 
the  trials  with  the  steam-whistle. 

Just  as  this  report  is  going  to  press  I  have  received  from    Report  of  Pro- 
Sir  Frederick  Arrow,  Professor  Tyndall's  report  of  the  fog- f< 
signal  experiments  at  South  Foreland,  which  the  former  has 
been  kind  enough  to  send  me  at  the  moment  of  its  publica- 
tion in  order  that  I  might  make  use  of  it  here,  and  1  take 
pleasure  in  interpolating  at  this  place  some  extracts  of  much 
interest. 

EXTRACTS  FROM  PROFESSOR  TYNDALL'S  REPORT  ON  FOG- 
SIGNALS. 

#  #  #  *  *  *  # 

"  May  20,  1873.—    *     *     *     There  was  nothing,  as  far    Guns  not  ai- 

T  .  ways  superior  to 

as  I  am  aware  of,  in  our  knowledge  of  the  transmission  of  horns  as  signals. 
sound  through  the  atmosphere,  to  invalidate  the  founding 
upon  these  experiments  of  the  general  conclusion  that,  as  a 
fog-signal,  the  gun  possessed  a  clear  mastery  over  the  horns. 
No  observation,  to  my  knowledge,  had  ever  been  made  to 
show  that  a  sound  once  predominant  would  not  be  always 
predominant,  or  that  the  atmosphere  on  different  days 


26  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

would  show  preferences  to  different  sounds.  A  complete 
reversal  of  the  foregoing  conclusion  was,  therefore,  not  to 
be  anticipated  ;  still,  on  many  subsequent  occasions,  it  was 

completely  reversed. 

*  *  *  *  *  *  * 

signals  on  top     "  The  observations  of  May  19  and  20  proved  that  no  ad- 

to  tho^eSateboS  vantage  was  gained  by  placing  the  horns  at  the  bottom 

tom-  of  the  cliff.     With  scarcely  an  exception  the  higher  horns 

proved  in  all  cases  slightly  superior  to  the  lower  ones.    In 

subsequent  experiments,  therefore,  the  higher  horns  alone 

were  for  the  most  part  invoked. 

*  ****** 

"June  3. — At  seven  miles  we  halted  ;  the  sound  of  the 
horns  was  here  very  distinct,  the  steam- whistle  being  also 
well  heard. 

"  While  in  this  position  an  exceedingly  heavy  rain-shower 
approached  at  a  galloping  speed.  It  could  hardly  have 
been  borne  forward  with  such  velocity  by  the  wind,  which 
had  only  a  force  of  2.  Its  advance  was  proba.bly  due  to  the 
rapid  successive  condensation  of  different  parts  of  the  same 
continuous  cloud.  The  sounds  were  not  sensibly  impaired 
during  the  continuance  of  the  rain.  Not  till  subsequently 
was  the  influence  of  such  a  shower  in  clearing  the  air  un- 
derstood. At  eight  miles  the  whistles  were  still  heard  and 
the  horns  better  heard.  At  nine  miles  the  whistles  ceased 
to  be  heard,  while  the  horns  continued  to  be  fairly  audible. 
TT  s  e  of  t  w  o  "  In  no  case  did  any  sensible  inequality  show  itself  between 
the  sound  of  the  single  horn  and  that  of  the  pair  of  horns. 
The  beats  of  the  two  horns  were,  however,  very  character- 
istic at  the  longer  distances.  The  blasts  of  the  horns  were 
not  of  uniform  strength;  even  in  the  same  blast  sudden 
swellings  out  and  fallings  off  of  the  sounds  were  observed. 

*  *  *  *  *  *  * 

Effect  of  the  "  June  11.—*  *  *  The  fall  of  the  sound  is  not  caused 
acoustic  shadow.  direct]y  by  tne  acOustic  shadow,  for  it  occurs  when  the  in- 
struments are  in  view  ;  but  the  limit  of  the  acoustic  shadow 
is  close  at  hand.  A  little  within  the  line  joining  the  Fore- 
land and  the  pier  end  the  instruments  are  cut  off  by  a  pro- 
jection of  the  cliff  near  the  station.  *  *  *  All  the  sea- 
space  between  this  'boundary'  and  the  cliff  under  Dover  Cas- 
tle is  in  the  shadow.  Into  this,  however,  the  direct  waves 
diverge,  and  lose  intensity  by  their  divergence,  the  portion 
of  the  wave  nearest  the  shadow  suffering  most.  Hence,  I 
doubt  not,  one  cause  of  the  decay  of  the  sound  in  the  posi- 
tion here  referred  to.  The  interference  of  sound  reflected 
from  the  cliff  with  the  direct  sound  doubtless  also  coutrib- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  27 

utes  to  the  effect.    Iii  establishing  a  fog-signal  station  such 

matters  must  be  carefully  attended  to. 

####### 

"  July  1.  —  *     *     *     Here  a  word  of  reflection  on  our    Accepted  theo- 

u  ry  01  loss  01  sound 

observations  may  be  fitly  introduced.    It  is  an  opinion  en-  ^  fog. 
tertaiued  in  high  quarters  that  the  waves  of  sound  are  re- 
flected at  the  limiting  surfaces  of  the  minute  particles  which 
constitute  haze  and  fog,  the  alleged  waste  of  sound  in  fog 
being  thus  explained.    Dr.  Bobinson,  for  example,  defines    Dr. 


fog  to  be  'a  mixture  of  air  and  globules  of  water,7  and  states  "e 
'  that  at  each  of  the  innumerable  surfaces  where  these  two 
touch  a  portion  of  the  vibration  is  reflected  and  lost.'  Theo- 
retically it  may  be  so  ;  but  if  this  were  an  efficient  practical 
cause  of  the  stoppage  of  sound,  it  would  be  difficult  to  un- 
derstand how  to-day,  in  a  thick  haze,  the  sound  reached  a 
distance  of  twelve  and  three-quarters  miles  ;  and  that  on 
May  20,  in  a  calm  and  hazeless  atmosphere,  the  maximum 
reach  of  the  sounds  was  only  from  five  to  six  miles.  Such 
facts  foreshadow  a  revolution  in  our  notions  regarding  the 

action  of  haze  and  fogs  upon  sound. 

******* 

"  July  2.  —  In  the  foregoing  observations  we  have  had  very  Fluctuations  in 
remarkable  fluctuations  in  the  range  of  the  sound,  that  range  rangeo 
vary  ing  from  three  or  four  miles  on  May  19  to  ten  and  one-half 
or  twelve  and  three-quarters  on  the  1st  of  July.  The  direc- 
tion and  force  of  the  wind,  known  to  exercise  a  potent  in- 
fluence upon  sound,  entirely  fail  to  account  for  these  fluc- 
tuations, nor  could  any  other  observed  meteorological  ele- 
ment be  held  responsible  for  them.  Prior  to  July  3  sur- 
mises more  or  less  vague  had  passed  through  my  mind  re- 
garding them  ;  but  all  remained  uncertain  until  on  the  3d 
surmise  and  perplexity  were,  to  a  great  extent,  displaced 
by  clear  physical  demonstration. 

"On  July  3  we  first  steamed  to  a  point  2.9  miles  southwest  Acoustic  opac- 
by  west  of  the  signal-station.  No  sounds,  not  even  the  ity  °f  air  July  3' 
guns,  were  heard  at  this  distance.  At  two  miles  they  were 
equally  inaudible.  But  this  being  the  position  in  which 
the  sounds,  though  strong  in  the  axis,  invariably  subsided, 
we  steamed  to  the  exact  bearing  from  which  our  observa- 
tions had  been  made  upon  July  1.  At  2.15  p.  m.,  and  at  a 
distance  of  three  and  three-quarters  miles  from  the  station, 
with  calm  air  and  a  smooth  sea,  the  horns  and  whistle 
(American)  were  sounded,  but  they  were  inaudible.  Sur- 
prised at  this  result,  I  signaled  for  the  guns.  They  were 
all  fired,  but,  though  the  smoke  seemed  at  hand,  no  sound 
whatever  reached  us.  On  July  1,  in  this  bearing,  the  range 


28  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

of  both  horns  and  guns  was  ten  and  a  half  miles.  We 
steamed  in  to  three  miles,  paused,  and  listened  with  all 
attention,  but  neither  horn  nor  whistle  was  heard.  The 
guns  were  again  signaled  for  $  five  of  them  were  fired  in 
succession,  but  not  one  of  them  was  heard.  We  steamed 
in  on  the  same  bearing  to  two  miles,  and  had  the  guns 
fired  point-blank  at  us.  The  howitzer  and  the  mortar,  with 
3-pound  charges,  yielded  a  feeble  thud,  while  the  IS-pounder 
was  wholly  unheard.  Applying  the  law  of  inverse  squares, 
it  follows  that,  with  air  and  sea  in  an  apparently  worse 
condition,  the  sound  at  two  miles  distance  on  July  1  must 
have  had  at  least  five-and  twenty  times  the  intensity  which 
it  possessed  at  the  same  distance  on, the  3d. 

"  With  the  Foreland  so  close  to  us,  the  sea  so  calm,  and  the 
air  so  transparent,  it  was  difficult,  indeed,  to  realize  that 
the  guns  had  been  fired  or  the  trumpets  sounded  at  all. 
What  could  have  caused  this  extraordinary  stifling  of  the 
sound?  Had  it  been  converted  by  internal  friction  into 
heat?  Or  had  it  been  wasted  in  partial  reflections  at  the 
limiting  surfaces  of  non-homogeneous  masses  of  air?  A 
few  words  will  render  this  question  intelligible  to  the  gen- 
eral reader.  Sulphur  in  homogeneous  crystals  is  exceed- 
ingly transparent  to  radiant  heat,  whereas  the  ordinary 
brimstone  of  commerce  is  highly  impervious  to  it.  Why? 
Because  the  brimstone  of  commerce  does  not  possess  the 
molecular  continuity  of  the  crystal,  but  is  a  mere  aggregate 
of  minute  grains  not  in  perfect  optical  contact  with  each 
other.  Where  this  is  the  case,  a  portion  of  the  heat  is 
always  reflected  on  entering  and  on  quitting  a  grain. 
Hence  when  the  grains  are  minute  and  numerous  this  re- 
flection is  so  often  repeated  that  the  heat  is  entirely  wasted 
before  it  can  plunge  to  any  depth  into  the  substance.  A 
snow-ball  is  opaque  to  light  for  the  same  reason.  It  is  not 
optically  continuous  ice,  but  an  aggregate  of  grains  of  ice, 
and  the  light  which  falls  upon  the  snow  being  reflected  at 
the  limiting  surfaces  of  the  snow-granules,  fails  to  pene- 
trate the  snow  to  any  depth.  Thus,  by  the  mixture  of  air 
and  ice,  two  transparent  substances,  we  produce  a  sub- 
stance as  impervious  to  light  as  a  really  opaque  one.  The 
same  remark  applies  to  foam,  to  clouds,  to  common  salt, 
indeed  to  all  transparent  substances  in  powder.  They  are 
all  impervious  to  light,  not  through  the  real  absorption  or 
extinction  of  the  light,  but  through  internal  reflection. 

"  Humboldt,  in  his  observations  at  the  Falls  of  the  Orinoco, 
? is  kll°wn  to  have  applied  these  principles.  He  found  the 
noise  of  the  falls  three  times  louder  by  night  than  by  day, 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  29 

though  in  that  region  the  night  is  far  noisier  than  the  day. 
The  plain  between  him  and  the  falls  consisted  of  spaces  of 
grass  and  rock  intermingled.  In  the  heat  of  the  day  he 
found  the  temperature  of  the  rock  to  be  30°  higher  than 
that  of  the  grass.  Over  every  heated  rock,  he  concludedf 
rose  a  column  of  air  rarefied  by  the  heat,  and  he  ascribed  the 
deadening  of  the  sound  to  the  reflections  which  it  endured 
at  the  limiting  surfaces  of  the  rarer  and  the  denser  air.  This 
philosophical  explanation  made  it  generally  known  that  a 
•non-homogeneous  atmosphere  is  unfavorable  to  the  trans- 
mission of  sound. 
"  But  what,  on  July  3,  with  a  calm  sea  as  a  basis  for  the  Reasons  for  the 

,  ,     non-  homogeneity 

atmosphere,  could  so  destroy  its  homogeneity  as  to  enable  of  the  a  tmo fl- 
it to  quench  in  so  short  a  distance  so  vast  a  body  of  sound?  p 
As  I  stood  upon  the  deck  of  the  Irene  pondering  this  ques- 
tion I  became  conscious  of  the  exceeding  power  of  the  sun 
beating  against  my  back  and  heating  the  objects  near  me. 
Beams  of  equal  power  were  falling  on  the  sea,  and  must 
have  produced  copious  evaporation.  That  the  vapor  gen- 
erated should  so  rise  and  mingle  with  the  air  as  to  form  an 
absolutely  homogeneous  mixture  I  considered  in  the  highest 
degree  improbable.  It  would  be  sure,  I  thought,  to  streak 
and  mottle  the  atmosphere  with  spaces  in  which  the  air 
would  be  in  different  degrees  saturated,  or  it  might  be  dis- 
placed by  the  vapor.  At  the  limiting  surfaces  of  these 
spaces,  though  invisible,  we  should  have  the  conditions  ne- 
cessary to  the  production  of  partial  echoes,  and  the  conse- 
quent waste  of  the  sound. 

"  Curiously  enough,  the  conditions  necessary  for  the  test-  clouds  causing 
ing  of  this  explanation  immediately  set  in.  At  3.15  p.  in.  ajjjj. 
cloud  threw  itself  athwart  the  sun  and  shaded  the  entirerea(lily- 
space  between  us  and  the  South  Foreland.  The  production 
of  vapor  was  checked  by  the  interposition  of  this  screen, 
that  already  in  the  air  being  at  the  same  time  allowed  to 
mix  with  it  more  perfectly $  hence  the  probability  of  im- 
proved transmission.  To  test  this  inference  I  had  the 
steamer  turned  and  urged  back  to  our  last  position  of  in- 
audibility. The  sounds,  as  I  expected,  were  distinctly 
though  faintly  heard.  This  was  at  three  miles'  distance.  At 
three  and  three-quarters  miles  we  had  the  guns  fired,  both 
point-blank  and  elevated.  The  faintest  pop  was  all  that  we 
heard  ;  but  we  did  hear  a  pop,  whereas  we  had  previously 
hoard  nothing,  either  here  or  three-quarters  of  a  mile  nearer. 
We  steamed  out  to  four  and  a  quarter  miles,  where  the  sounds 
were  for  a  moment  faintly  heard  ;  but  they  fell  away  as  we 
waited,  and  though  the  greatest  quietness  reigned  on  board, 


30  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

and  though  the  sea  was  without  a  ripple,  we  could  hear 
nothing.  We  could  plainly  see  the  steam-puffs  which  an- 
nounced the  beginning  and  end  of  a  series  of  trumpet-blasts, 
but  the  blasts  themselves  were  quite  inaudible. 

"It  was  now  4  p.  m.,  and  my  intention  at  first  was  to  halt 
at  this  distance,  which  was  beyond  the  sound-range,  but 
not  far  beyond  it,  and  see  whether  the  lowering  of  the  sun 
would  not  restore  the  power  of  the  atmosphere  to  transmit 
the  sound.  But,  after  waiting  a  little,  the  anchoring  of  a 
boat  was  suggested,  so  as  to  liberate  the  steamer  for  other 
work ;  and  though  loath  to  lose  the  anticipated  revival  of  the 
sound  myself,  I  agreed  to  this  arrangement.  Two  men  were 
placed  in  the  boat  and  requested  to  give  all  attention  so  as 
to  hear  the  sound  if  possible.  With  perfect  stillness  around 
them  they  heard  nothing.  They  were  then  instructed  to 
hoist  a  signal  if  they  should  hear  the  sounds,  and  to  keep  it 
hoisted  as  long  as  the  sound  continued. 

"  At  4.45  we  quitted  them  and  steamed  toward  the  South 
Sand  Head  light-ship.  Precisely  15  minutes  aftefe  we  had 
separated  from  them  the  flag  was  hoisted.  The  sound  had 
at  length  succeeded  in  piercing  the  body  of  air  between  the 
boat  and  the  shore. 

"  We  continued  our  journey  to  the  light-ship,  went  on 
board,  and  heard  the  report  of  the  light sm en.  Eeturning 
toward  the  Foreland,  in  answer  to  a  signal  expressing  a 
wish  to  communicate  with  us,  we  manned  a  boat  and  pulled 
to  the  shore.  The  exhaustion  of  the  ammunition  was  re- 
ported, but  the  horns  and  whistle  continued  to  sound.  We 
steamed  out  to  our  anchored  boat,  and  then  learned  that 
when  the  flag  was  hoisted  the  horn -sounds  were  heard  ; 
that  they  were  succeeded  after  a  little  time  by  the  whistle- 
sounds,  and  that  both  increased  in  intensity  as  the  evening 
advanced.  On  our  arrival,  of  course  we  heard  the  sounds 
ourselves. 

"The  explanation  given  above  of  the  stoppage  of  the  sound 
is  in  perfect  harmony  with  these  observations.  But  we 
pushed  the  test  further  by  steaming  farther  out.  At  five 
and  three-quarters  miles  we  halted  and  heard  the  sounds. 
At  six  miles  we  heard  them  distinctly,  but  so  feebly  that 
we  thought  we  had  reached  the  limit  of  the  sound-range. 
But  while  we  waited  the  sound  rose  in  power.  We  steamed 
to  the  Varne  buoy,  which  is  seven  and  three-quarters  miles 
from  the  signal- station,  and  heard  the  sounds  there  better 
than  at  six  miles  distance.  We  continued  our  course  out- 
ward to  ten  miles,  halted  there,  but  heard  nothing. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  31 

"At  eight  miles'  distance  the  sound  in  the  evening  was  at    signals  heard 

rr\i      i  a*  eight  miles  in 

least  as  well  heard  as  at  two  miles  in  the  morning.    That  the  evening. 
this  could  occur  it  was  necessary,  in  accordance  with  the 
law  of  inverse  squares,  that  the  sound  at  two  miles'  distance 
should  have  risen  in  the  evening  to  an  intensity  at  least  six- 
teen times  that  which  it  possessed  in  the  morning. 

"  Steaming  on  to  the  Varne  light-ship,  which  is  situated  at 
the  other  end  of  the  Yarne  Shoal,  we  hailed  the  master,  and 
were  informed  by  him  that  up  to  5  p.  m.,  nothing  had  been 
heard.  At  that  hour  the  sounds  began  to  be  audible.  He 
described  one  of  them  as  i  very  gross,  resembling  the  bel- 
lowing of  a  bull,'  which  very  accurately  characterizes  the 
sound  of  the  large  American  steam -whistle.  At  the  Varne 
light-ship,  therefore,  the  sounds  had  been  heard  toward  the 
close  of  the  day,  though  it  is  twelve  and  three-quarters  miles 
from  the  signal-station.  On  our  return  to  Dover  Bay  at  10 
p.  m.  we  heard  the  sounds,  not  only  distinct  but  loud, 
where  nothing  could  be  heard  in  the  morning. 

"I  have  already  referred  to  the  winds  and  currents  which  winds  and  cur- 
establish  themselves  round  the  South  Foreland.  Mr.  Holmes  Foreland. 
was,  as  usual,  there  on  July  3,  and  he  informed  me  that, 
from  the  motion  of  the  smoke  of  some  passing  steamers  and 
from  the  sails  of  sailing- vessels,  he  could  recognize  a  curious 
circulation  of  the  air  from  laud  to  sea.  The  wind  would 
sometimes  hug  the  cliff  to  the  northeast  of  the  Foreland ; 
then  bend  around  and  move  toward  the  South  Sand  Head 
light-ship.  And,  in  point  of  fact,  the  wind  at  the  light- 
vessel  had  been  southwest,  with  a  force  of  3  nearly  the 
whole  of  the  day;  whereas  with  us  it  had  passed  from  south- 
west by  west  to  a  dead  calm,  and  afterward  to  southeast.  On 
shore  also  it  had  shifted  from  southwest  to  southeast.  The 
atmospheric  conditions  between  the  light-vessels  and  the 
Foreland  were,  therefore,  different  from  those  between  us 
and  the  Foreland;  and  the  consequence  was  that  at  the  time 
when  we  were  becalmed  and  heard  nothing  the  light-keepers, 
with  the  larger  component  of  a  wind  of  3  acting  against  the 
sounds,  heard  them  plainly  all  day. 

"  But  both  the  argument  and  the  phenomena  have  a  com-  Reflection  of 
plementary  side,  which  we  have  now  to  consider.  A  stratum 
of  air  three  miles  thick  on  a  perfectly  calm  day  has  been 
proved  competent  to  stifle  both  the  cannonade  and  the  horn 
sounds  employed  at  the  South  Foreland ;  while  the  observa- 
tions just  recorded  seem  to  point  distinctly  to  the  mixture 
of  air  and  aqueous  vapor  as  the  cause  of  this  extraordinary 
phenomenon.  Such  a  mixture  could  fill  the  atmosphere  with 


32  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

an  impervious  acoustic  cloud  on  a  day  of  perfect  optical  trans- 
parency. But,  granting  this,  it  is  incredible  that  so  great 
a  body  of  sound  could  utterly  disappear  in  so  short  a  distance 
without  rendering  any  account  of  itself.  Supposing,  then, 
instead  of  placing  ourselves  behind  the  acoustic  cloud,  we 
were  to  place  ourselves  in  front  of  it,  might  we  not,  in 
accordance  with  the  law  of  conservation,  expect  to  receive 
by  reflection  the  sound  that  had  foiled  to  reach  us  by  trans- 
mission? The  case  would  then  be  strictly  analogous  to 
the  reflection  of  light  from  an  ordinary  cloud  to  an  observer 
placed  between  it  and  the  sun. 

Echoes  ob-  «  My  first  care  in  the  early  part  of  the  day  in  question  was 
to  assure  myself  that  our  inability  to  hear  the  sound  did 
not  arise  from  any  derangement  of  the  instruments  on  shore. 
Accompanied  by  Mr.  Edwards,  who  was  good  enough  on 
this  and  some  other  days  to  act  as  my  amanuensis,  at  1  p. 
m.  I  was  rowed  to  the  shore,  and  landed  at  the  base  of  the 
South  Foreland  cliff.  The  body  of  .sir  which  had  already 
shown  such  extraordinary  power  to  intercept  the  sound, 
and  which  manifested  this  power  still  more  impressively 
later  in  the  day,  was  now  in  front  of  us.  On  it  the  sono- 
rous waves  impinged,  and  from  it  they  were  sent  back  to 
us  with  astonishing  intensity.  The  instruments,  hidden 
from  view,  were  on  the  summit  of  a  cliff  235  feet  above  us, 
the  sea  was  smooth  and  clear  of  ships,  the  atmosphere  was 
without  a  cloud,  and  there  was  no  object  in  sight  which 
could  possibly  produce  the  observed  effect.  From  the  per- 
fectly transparent  air  the  echoes  came,  at  first  with  a  strength 
apparently  but  little  less  than  that  of  the  direct  sound,  and 
then  dying  gradually  and  continuously  away.  A  remark 
made  by  my  talented  companion  in  his  note-book  at  the  time 
shows  how  the  phenomenon  affected  him.  'Beyond  saying 
that  the  echoes  seemed  to  come  from  the  expanse  of  ocean, 
it  did  not  appear  possible  to  indicate  any  more  definite  point 
of  reflection.'  Indeed,  no  such  point  was  to  be  seen  ;  the 
echoes  reached  us,  as  if  by  magic,  from  absolutely  invisible 
walls. 

u  Here,  I  doubt  not,  we  have  the  key  to  many  of  the  mys- 
teries and  discrepancies  of  evidence  which  beset  this  ques- 
tion. The  foregoing  observations  show  that  there  is  no 
need  to  doubt  either  the  veracity  or  capability  of  the  con- 
flicting witnesses,  for  the  variations  of  the  atmosphere  are 
more  than  sufficient  to  account  for  theirs.  The  mistake,  in- 
deed, hitherto  has  been,  not  in  reporting  incorrectly,  but  in 
neglecting  the  monotonous  operation  of  repeating  the  ob- 
servations during  a  sufficient  time.  I  shall  have  occasion 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  33 

to  remark  subsequently  on  the  mischief  likely  to  arise  from 
givine:  instructions  to  mariners  founded  on  observations  of 
this  incomplete  character. 

"  The  more  accurate  comprehension  of  various  historic    striking  cases 

1  of   non-transrais- 

occurrences  will  be  rendered  possible  by  these  observations,  sum  of  sound. 
In  his  lecture  entitled  l  Wirkungen  aus  der  Feme,'  the  emi- 
nent Berlin  philosopher,  Dove,  has  collected  some  striking 
cases  of  this  kind.  During  the  battle  of  Cassano,  on  the 
Adda,  between  the  Due  tie  Vendome  and  the  Prince  Eugene, 
an  army -corps  stationed  under  the  duke's  brother,  five 
miles  up  the  river,  failed  to  join  the  battle  through  not 
hearing  the  cannonade.  In  a  river-valley,  particularly  on 
a  warm  day,  it  would,  in  my  opinion,  be  very  perilous  to 
place  much  dependence  upon  sound.  Near  Montereau,  on 
the  Seine,  during  the  battle  between  Napoleon  I  and  the 
King  of  Wiirtemberg,  which  lasted  seven  hours,  no  sound 
of  the  conflict  was  heard  by  Prince  Schwartzenberg,  thirteen 
miles  up  the  river.  A  Prussian  officer  sent  thither  at  noon 
first  heard  the  cannonade  at  a  distance  of  four  and  a  half 
miles  from  the  field  of  battle.  This  happened  on  a  day 
apparently  resembling  in  point  of  mildness  and  serenity  our 
3d  of  July.  In  the  battle  of  Liegnitz,  where  Frederick  the 
Great  overthrew  Laudon,  the  sound  of  the  battle  was  un- 
heard by  Field-Marshal  Daun,  who  was  posted  on  a  height 
four  and  a  half  miles  from  the  battle-field.  Dove  himself 
recounts  the  fact  of  his  having  failed  to  catch  a  single  shot 
of  the  battle  of  Katzbach,  at  four  and  a  half  miles  distance, 
while  he  plainly  heard  the  cannonade  of  Bautzen,  eighty 
miles  away. 

"  The  stoppage  of  the  sound  in  the  foregoing  cases  Dove   other  instances 
referred,  and  doubtless  correctly,  to  the  non-homogeneous  Jfe 
character  of  the  air.     He  also  notes  the  exceedingly  inter- phere" 
estiug  observation  that  in  certain  clear  winter  days,  when 
the  sun  has  already  attained  some  power,  the  semaphore  is 
difficult  to  decipher,  the  reason  being  that  by  the  solar 
warmth  upward  currents  of  warm  and  downward  currents 
of  cold  air  (similar  to  those  of  Humboldt  on  the  plain  of 
Autures)  are  established,  and  that  such  days  are  also  un- 
favorable to  the  transmission  of  sound.    In  another  pas- 
sage, however,  he  seems  to  endorse  the  prevalent  notion 
that  the  transparency  of  the  air  and  its  power  to  transmit 
sound  go  hand  in  hand  ;  whereas  in  our  experiments  days 
of    the  highest  optical  transparency  proved  themselves 
acoustically  most  opaque. 

"  <  Over  water,'  says  Sir  John  Herschel,  « or  a  surface  of 
ice,  sound  is  propagated  with    remarkable  clearness  and 
S.  Ex.  54 3 


34  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

strength  ; '  and  he  refers  to  the  well-known  case  of  Lieu- 
tenant Foster,  who,  in  the  polar  expedition  of  Captain 
Parry,  carried  on  a  conversation  across  the  frozen  harbor  of 
Port  Bowen,  which  is  a  mile  and  a  quarter  wide.  But  as 
regards  smoothness,  water  could  hardly  be  in  a  better  con- 
dition than  the  sea  between  the  Irene  and  the  South  Fore- 
land on  the  3d  of  July.  Still,  though  aided  by  reflection 
from  the  sea's  surface,  the  sound  was  powerless  to  penetrate 
the  air.  And  in  regard  to  Lieutenant  Foster's  observation, 
there  cannot,  I  think,  be  a  doubt  that  the  extraordinary 
acoustic  transparency  of  the  polar  atmosphere  is  mainly  due 
to  the  absence  of  that  flocculence  which  in  our  observations 
proved  so  hostile  to  the  transmission  of  the  sound.  To  the 
same  cause  is,  I  believe,  to  be  ascribed  the  hearing  of  can- 
nonades at  the  extraordinary  distances  of  eighty,  one  hun- 
dred and  eighty,  and  two  hundred  miles,  mentioned  by  Sir 
John  Herschel  in  his  essay  on  sound.  Had  Humboklt  him- 
self been  aware  of  the  observations  here  recorded,  might  not 
his  classical  observation  also  have  been  connected  with  the 
vapor  raised  from  the  Orinoco  by  a  tropical  sun  I 
Experiments  "  In  the  celebrated  experiments  conducted  by  the  cominis- 
v!l£^Tam£i  sion  of  the  French  Bureau  des  Longitudes  in  1822,  two  sta- 
des  Longitudes.  tioDS  were  chosen,  11.6  miles  apart,  the  one  at  Montlhery, 
and  the  other  at  Villejuif,  near  Paris.  Two  remarkable 
phenomena,  which  have  a  special  interest  in  relation  to  our 
observations,  presented  themselves  to  the  observers ;  the 
one  was  that  while  the  report  of  every  gun  fired  at  Mont- 
lhery was  exceedingly  well  heard  at  Villejuif,  by  far  the 
greater  number  of  those  fired  at  Yillejuif  failed  to  be  heard  at 
Montlhery.  In  reference  to  this  point  Arago,  the  writer  of 
the  report,  with  that  philosophic  reserve  which  he  showed 
in  other  matters,  expressed  himself  thus :  'Quant  aux  diffe"- 
rences  si  remarquables  d'intensite  que  le  bruit  du  canon  a 
toujours  presentees  suivant  qu'il  se  propageait  du  nord  au 
sud  entre  Villejuif  et  Montlhery,  ou  du  sud  au  nord  entre 
cette  seconde  station  et  la  premiere,  nous  ne  chercherons 
pas  aujourd'hui  a  les  expliquer,  parceque  nous  ne  pourrions 
offrir  au  lecteur  que  des  conjectures  denuees  des  preuves.' 
To  another  phenomenon  he  also  directs  attention,  offering 
not  only  a  description,  but  an  explanation  :  '  Avant  de  ter- 
miner  cette  note,  nousajouterons  seulement  que  tous  les 
coups  tires  a  Montlhery  y  etaient  accompagnes  d'un  roule- 
ment  semblable  a  celui  da  tonnerre,  et  qui  durait  20"  a  25". 
Biende  pareil  n'avait  lieua  Villejuif $  il  nous  est  arrive"  seule- 
raent  d'eutendre,  a  moins  d'une  seconde  d'intervalle,  deux 
coups  distincts  du  canon  de  Moutlhery.  Dans  deux  autres 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  35 

circonstanees  le  bruit  de  ce  canon  a  ete  accoinpagne"  d'un 
roulemeut  prolonge.  Ces  pheuoinenes  n'ont  jamais  eu  lieu 
qu'au  moment  d7  apparition  de  quelques  uuages  ;  par  un  ciel 
completement  serein  le  bruit  etait  unique  et  instantane. 
Ke  serait-il  pas  permis  de  conclure  de  la  qu'a  Villejuif  les 
coups  multiples  du  canon  de  Montlhery  resultaient  d'echos 
formes  dans  les  nuages,  et  de  tirer  de  ce  fait  un  argument 
favorable  a  Fexplication  qu'ont  donne"e  quelque  physi- 
•cieus  du  roulement  du  tonnerreT 

"  It  is  not  here  stated,  that  at  Montlhery  the  clouds  were 
seen  when  the  echoes  were  heard.  The  explanation  of  the 
Montlhery  echoes  is  in  fact  an  inference  from  observations 
made  at  Villejuif.  I  think  that  inference  requires  qualifica- 
tion .  Some  hundreds  of  cannon-shots  have  been  fired  at  the 
South  Foreland,  many  of  them  when  the  heavens  were  com- 
pletely free  from  clouds,  and  never  in  a  single  case  has 
a  'rotilement*  similar  to  that  noticed  at  Montlhery  been  ab- 
sent. It  follows,  moreover,  so  hot  upon  the  direct  sound  as 
to  present  scarcely  a  sensible  breach  of  continuity  between 
the  sound  and  the  echo.  This  could  not  be  the  case  if  the 
clouds  were  its  origin.  A  reflecting  cloud,  even  at  the  short 
distance  of  1,000  yards,  would  leave  a  silent  interval  of  five 
seconds  between  the  sound  and  the  echo.  Had  such  an  inter- 
val been  observed  at  Montlhery  it  could  hardly  have  escaped 
record  by  the  philosophers  stationed  there. 

"  But,  to  fall  back  from  reasoning  upon  facts,  it  is  certain  Echoes  produced 
that  air  of  perfect  visual  transparency  is  competent  to  pro-  air.tra 
duce  echoes  of  great  intensity  and  long  duration.  I  shall 
have  further  occasion  to  refer  to  such  echoes $  for  it  was  not 
with  whistles,  nor  trumpets,  nor  guns,  that  these  echoes  in 
our  observations  reached  their  greatest  development,  but 
with  the  steam-siren,  to  be  described  farther  on.  The  blasts 
sounded  by  this  instrument  number,  I  believe,  about  twenty 
thousand  5  but  whatever  might  be  the  state  of  the  weather, 
cloudy  or  serene,  stormy  or  calm,  no  single  blast  of  the  siren 
failed  to  be  accompanied  by  echoes  of  astonishing  strength. 

"  The  other  point  referred  to,  which  Arago  declined  to  dis- 
cuss, presents  a  grave  difficulty.  No  attempt,  as  far  as  I 
am  aware  of,  has  since  been  made  to  solve  it,*or  even  to  show 
that  a  solution  is  conceivable.  I  think  the  foregoing  obser- 
vations might  be  shown  to  have  some  bearing  upon  the  point. 
Arago  makes  incidently  the  significant  remark  that,  on  June 
22,  when  only  one  out  of  twelve  of  the  shots  fired  at  Ville- 
juif was  heard,  and  that  feebly,  at  Montlhery,  '  Thygrometre 
avait  marche  beaucoup  a  1'humidite;'  and  farther  on  he 
speaks  of  the  air  as  i  tout  pres  du  terme  de  1'humidite  ex- 


36  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

treine.'  I  believe  myself  safe  in  saying  that  air  thus  moving 
rapidly  toward  its  point  of  saturation  is  sure  to  yield  echoes; 
and  the  fact  that  echoes  were  heard  at  Montlhery  and  not  at 
Villejuif  is  a  proof  of  the  different  hygrometric  condition  of 
the  air  at  the  two  stations.  With  the  light  wind  recorded 
in  the  report,  Montlhery  would  probably  be  swathed  by 
vapor  from  the  valley  of  the  Seine.  It  seems  to  me  by  no 
means  impossible  to  imagine  a  distribution  of  vapor  sufficient 
to  produce  the  observed  effect;  but  this  is  a  subject  which 
may  be  reserved  for  future  investigation. 

"  The  observations  of  July  3, 1  believe,  reveal  to  us  the 
most  potent  cause  of  the  caprices  of  the  atmosphere  as  re- 
gards the  transmission  of  sound.  We  shall,  moreover,  find 
them  throwing  light  upon  anomalies  subsequently  observed, 
which,  without  their  aid,  would  be  perplexing  in  the  high- 
est degree. 

*  *  *  *  #  *  *  • 

American  siren  "  During  my  recent  visit  to  the  United  States  I  was 
S?nt.f°r  esperi"  favored  by  an  introduction  to  General  Woodruff  by  Professor 
Joseph  Henry,  of  Washington.  Professor  Henry  is  chair- 
man of  the  Light-House  Board,  and  General  Woodruff  is 
engineer  in  charge  of  two  of  the  light-house  districts.  I 
accompanied  General  Woodruff'  to  the  establishment  at 
Staten  Island,  and  afterward  to  Sandy  Hook,  with  the 
express  intention  of  observing  the  performance  of  the 
steam-siren  which,  under  the  auspices  of  Professor  Henry, 
has  been  introduced  into  the  light-house  system  of  the 
United  States.  Such  experiments  as  were  possible  to  make 
under  the  circumstances  were  made,  and  I  carried  home 
with  me  a  somewhat  vivid  remembrance  of  the  mechanical 
effect  of  the  sound  of  the  steam-siren  upon  my  ears  and 
body  generally.  This  I  considered  to  be  greater  than  the 
similar  effect  produced  by  the  horns  of  Mr.  Holmes ;  hence 
the  desire,  on  my  part,  to  see  the  siren  tried  at  the  South 
Foreland.  The  formal  expression  of  this  desire  was  antici- 
pated by  the  Elder  Brethren,  while  their  wishes  were  in 
turn  anticipated  by  the  courteous  kindness  of  the  Light- 
House  Board  at  Washington.  Informed  by  Major  Elliot 
that  our  experiments  had  begun,  the  Board  forwarded  to 
the  corporation,  for  trial,  the  noble  instrument  now  mounted 
at  the  South  Foreland. 

Principle  of  the  "The  principle  of  the  siren  is  easily  understood.  A  mu- 
sical sound  is  produced  when  the  tympanic  membrane  is 
struck  periodically  with  sufficient  rapidity.  The  production 
of  these  tympanic  shocks  by  puffs  of  air  was  first  realized  by 
Doctor  Eobisou,  and  his  device  was  the  first  and  simplest 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  37 

form  of  the  siren.  A  stop-cock  was  so  constructed  that  it 
opened  and  shut  the  passage  of  a  pipe  seven  hundred  and 
twenty  times  in  a  second.  Air  being  allowed  to  pass  inter- 
mittently along  the  pipe  by  the  rotation  of  the  cock,  4a  mu- 
sical sound  was  most  smoothly  uttered.'  A  great  step  was 
made  in  the  construction  of  this  instrument  by  Cagniard  de 
la  Tour,  who  gave  it  its  present  name.  He  employed  a  box 
with  a  perforated  lid,  and  above  the  lid  a  similarly  perfo- 
rated disk,  capable  of  rotation.  The  perforations  were 
oblique,  so  that  when  wind  was  driven  through,  it  so  im- 
pinged upon  the  apertures  of  the  disk  as  to  set  it  in  motion. 
No  separate  mechanism  was  therefore  required  to  move  the 
upper  disk.  When  the  perforations  of  the  two  disks  coin- 
cided, a  puff  escaped  ;  when  they  did  not  coincide,  the  cur- 
rent of  air  was  cut  off.  In  this  way  a  succession  of  im- 
pulses was  imparted  to  the  air.  The  siren  has  been 
greatly  improved  by  Dove,  and  specially  so  by  Helmholtz. 
Even  in  its  small  form  the  instrument  is  capable  of  produc- 
ing sounds  of  great  intensity. 

uln  the  steam-siren,  patented  by  Mr.  Brown,  of  New  York, 
a  fixed  disk  and  a  rotating  disk  are  also  employed,  radial 
slits  being  cut  in  both  disks  instead  of  circular  apertures. 
One  disk  is  fixed  across  the  throat  of  a  trumpet,  1CJ  feet 
long,  5  inches  in  diameter,  where  the  disk  crosses  it,  and 
gradually  opening  out  till  at  the  other  extremity  it  reaches 
a  diameter  of  2  feet  3  inches.  Behind  the  fixed  disk  is  the 
rotating  one,  which  is  driven  by  separate  mechanism.  The 
trumpet  is  mounted  on  a  boiler.  In  our  experiments  steam 
of  70  pounds  pressure  has  for  the  most  part  been  employed. 
Just  as  in  the  siren  already  described,  when  the  radial 
slits  of  the  two  disks  coincide,  a  puff  of  steam  escapes. 
Sound-waves  of  great  intensity  are  thus  sent  through  the 
air  ;  the  pitch  of  the  note  produced  depending  on  the 
rapidity  with  which  the  puffs  succeed  each  other  ;  in  other 
words,  upon  the  velocity  of  rotation. 

******* 

"  October  8.  —  *     *     *    The  heavy  rain  at  length  reached  sound  not  dead- 


us,  but  although  it  was  falling  all  the  way  between  us  and  ra. 
the  Foreland,  the  sound,  instead  of  being  deadened,  rose 
perceptibly  in  power.  Hail  was  now  added  to  the  rain,  and 
the  shower  reached  a  tropical  violence.  The  deck  was 
thickly  covered  with  hail-stones,  which  here  and  there 
floated  upon  the  rain-water,  the  latter  not  having  time  to 
escape.  We  stopped.  In  the  midst  of  this  furious  squall 
both  the  horn  and  the  siren  were  distinctly  heard  j  and  as 
the  shower  lightened,  thus  lessening  the  local  noises,  the 


38  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

sounds  so  rose  in  power  that  we  heard  them  at  a  distance 
of  seven  and  a  half  miles  distinctly  louder  than  they  had 
been  heard  through  the  rainless  atmosphere  at  five  miles. 
This  observation  is  entirely  opposed  to  the  statement  of 
Derhain,  which  has  been  repeated  by  all  writers  since  his  time, 
regarding  the  stifling  influence  of  falling  rain  upon  sound. 
But  it  harmonizes  perfectly  with  our  experience  on  the  3d 
July,  which  proved  water  in  the  state  of  vapor ,  so  mixed  with 
air  as  to  form  non-homogeneous  parcels,  to  be  a  most  potent 
influence  as  regards  the  stoppage  of  sound.  Prior  to  the 
violent  showers  of  to-day  the  air  had  been  in  this  condition, 
but  the  descent  of  the  shower  restored  in  part  the  homoge- 
neity of  the  atmosphere  and  auguinented  its  transmissive 
power. 

"  In  the  cleansed  and  cool  atmosphere  the  horn-sound  ap- 
peared to  improve  more  than  that  of  the  siren,  slightly 
surpassing  it  at  times.  The  horn-note  was  of  lower  pitch  ; 
hence  it  might  be  inferred  that  the  change  in  the  atmos- 
phere favored  specially  the  transmission  of  the  longer  waves. 

"  Up  to  this  time  the  siren  had  been  performing  2,400 
revolutions  a  minute ;  the  rate  was  now  reduced  to  2,000  a 
minute.  The  sound  immediately  surpassed  that  of  the  horn. 
By  this  experiment  the  foregoing  inference  was  reduced  to 
demonstration;  a  highly  instructive  result,  as  it  showed  an 
interdependence  between  aerial  reflection  and  the  lengths 
of  the  sonorous  waves. 

"At  4  p.  m.  the  rain  had  ceased,  the  sun  shone  clearly 
out :  the  air  was  calm  afloat,  but  west  with  a  force  of  2, 
ashore.  At  nine  miles'  distance  the  horn  was  heard  feebly, 
the  siren  clearly ;  the  howitzer  at  this  distance  sent  us  a 
loud  report.  All,  indeed,  seemed  better  at  this  distance 
than  at  five  and  one  half  miles;,  from  which  it  follows  that 
at  this  latter  distance  the  intensity  of  the  sound  must  have 
been  augmented  at  least  threefold  by  the  descent  of  the 

rain. 

******* 

"  October  10.—*  *  *  We  descended  the  12-ladder  shaft, 
and  from  the  lower  station  listened  to  the  gun,  the  upper 
horn,  the  siren,  and  the  lower  horn.  The  sound  of  the 
siren  was  strikingly  distinguished  from  that  of  the  upper 
horn  by  its  hardness  and  almost  explosive  force.  Its  echoes 
also  were  much  louder  and  longer  continued  than  those  of 
the  horn  ;  and  from  this  alone  its  greater  reach  of  penetra- 
tion might  be  inferred.  The  noise  of  the  surf,  however,  at 
the  lower  station,  interfered  seriously  with  the  observa- 
tions. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  39 

"  October  13.—*  *  *  On  steaming  toward  the  axis  no 
echo  for  some  time  was  generated  by  the  horns,  none  by  the 
Canadian  whistle,  but  long-drawn  and  distinct  echoes  carae 
from  the  south  in  the  case  of  the  siren.  When  quite 
abreast  of  the  station  the  horn-echoes  were  also  heard,  but 
they  failed  to  approach  in  intensity  those  of  the  siren. 

"  Near  the  shore  the  wind  was  now  north ;  farther  out  it  was  yh  ?a(JJ'R!? 
southwest,  and  we  steamed  between  the  two  currents.  As  cribed  to  rain. 
far  as  the  South  Sand  Head  light-ship  all  the  sounds  were 
heard  both  through  violent  rain  and  through  the  noise  of  the 
paddles.  To  rain  I  have  never  yet  been  able  to  trace  any 
deadening  power ;  indeed  such  rain  as  we  have  hitherto  en- 
countered produced  a  distinctly  opposite  effect,  and  the 
reason  is  now  intelligible.  The  siren  on  the  present  occa- 
sion was  clearest  and  loudest,  though  at  times  the  Cana- 
dian whistle  showed  great  power.  A  struggle  between  the 
winds  continued  for  some  time,  the  north  wind,  accompanied 
by  a  cool  atmosphere,  at  length  prevailing. 

"Once  while  halting  near  the  light-ship,  when  the  Fore-    superiority  of 

...»t-.          •  ,,tho     Americau 

land  was  hidden  in  a  dense  ram-mist,  I,  Lemg  ignorant  ol  siren, 
its  bearing,  immediately  found  its  position  from  the  direc- 
tion of  the  sound. 

"Thomson,  the  chief  lamp-lighter  at  the  South  Sand  Head, 
an  exceedingly  intelligent  man,  reported  that  on  all  occa- 
sions the  sound  of  the  siren  had  the  mastery;  and  that 
opinion  011  this  point  was  unanimous  on  board  the  light- 
vessel.  On  Friday  and  Saturday  the  sounds,  he  reported, 
were  but  faintly  heard,  being  probably  impaired  by  the  lo- 
cal noises.  To-day  we  found  during  our  visit  all  the  sounds 

very  good,  that  of  the  siren  being  particularly  intense. 

*  *  *  *  *  *  * 

"  October  14.—*     *     *     At  11.30  a.  m.  a  gun  was  fired  at    Error  in  sup- 
posing   a   shrill 
the  Foreland  ;  report  distinct.    Up  to  this  time  the  Cana-  note  to  be  supe- 

rior  as  a  signal. 

dian  whistle  had  been  adjusted  to  produce  a  shrill  note  ;  it 
was  not  heard.  The  piercing  shrillness  of  this  note,  when 
heard  at  the  South  Foreland  on  October  10,  suggested  its 
trial  to-day.  The  opinion  that  a  note  of  this  character, 
which  affects  an  observer  close  at  hand  so  powerfully  and 
painfully,  has  also  the  greatest  range,  is  a  common  one,  and 
might  be  true  in  connection  with  homogeneous  atmosphere. 
But  in  'flocculent'  air  the  shorter  waves  suffer  most  from  par- 
tial reflection,  exactly  as  the  shorter  waves  of  solar  light 
suffer  most  in  their  passage  through  the  suspended  matter 
of  the  atmosphere.  The  blue  of  the  firmament  is,  in  fact, 
the  echo  of  these  shorter  undulations. 


40  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

"According  to  arrangement,  the  Canadian  whistle  was  now 
changed  to  its  old  low  pitch.  It  was  immediately  heard  at 

the  Varne  buoy. 

******* 

"  During  the  earlier  part  of  this  day  the  atmosphere,  which, 

throughout,  was  of  extreme  optical  clearness,  favored  the 

transmission  of  the  longer  sound-waves,  corresponding  to  the 

deeper  sounds. 

changes  in  the     "After  a  lapse  of  three  hours  the  case  was  reversed,  the 

atmosphere      on  ,  , 

the  same  day.  high-pitched  siren  being  heard  when  both  gun  and  horns 
were  absolutely  inaudible.  But  even  this  was  not  perma- 
nent. Such  changes  on  the  part  of  the  atmosphere  have 
never  hitherto  been  noticed,  nor  am  I  aware  of  a  single  ob- 
servation bearing  upon  this  selective  stoppage  of  the  sound. 
Its  optical  analogies  have  been  already  pointed  out.  The 
parcels  of  air  and  vapor  play,  to  some  extent,  the  same  part 
in  scattering  the  waves  of  sound  as  the  minute  particles  sus- 
pended in  the  atmosphere  do  in  scattering  the  solar  light, 
producing  by  their  preferences  in  this  respect  the  blue  of 
the  sky. 

******* 

Daboii's  inven-     "  October  15.—*    *     *    To  the  late  Mr.  Daboll,  of  the 

tion  of  fog-horns.  unite(l  States,  belongs  the  credit  of  bringing  large  trumpets 

into  use  as  fog-signals.    At  Dungeness  one  of  his  horns  had 

been  erected  under  his  own  superintendence  ;  and  wishing 

to  make  myself  acquainted  with  its  performance,  we  steamed 

Horn  at  Dun- thither  to-day.  On  examining  the  horn,  I  was  struck  by 
its  similarity  in  all  essential  particulars  to  the  horns  em- 
ployed at  the  South  Foreland.  Considerable  improvements 
in  the  working  of  the  horn  have  been  introduced  by  Mr. 

Holmes,  but  the  horn  itself  is  substantially  that  of  Daboll. 

******* 

"  October  18. — *  *  *  There  is  no  doubt  that  two  days 
might  be  chosen  on  one  of  which  the  report  of  a  pocket-pis- 
tol would  be  further  heard  than  the  report  of  an  18-pounder 
on  the  other.  *  *  *  * 

"October  23. — *     *     *     In  the  observations  of  Mr.  Ayres 

to  the  west  of  the  Foreland,  wind  and  sound  were  almost  in 

direct  opposition  ;  in  those  of  Mr.  Douglass  they  were  by 

no  means  coincident.    For  a  time  both  directions  inclosed  an 

angle  of  about  45°,  and  subsequently  a  greater  angle.    The 

Effect  of  athun-  difference  in  the  results  is  nevertheless  striking.    I  may  here 

atmSpheerreOIltbe  draw  attention  to  the  remarkable  effect  of  the  rain  and 

thunder-storm  observed  by  Mr.  Douglass.     He  was  well 

in  the  sound-shadow  near  Kingsdown  coast-guard  station. 

He  had  sent  a  fly  in  advance  of  him,  and  the  driver  had 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  41 

been  waiting  for  him  for  fifteen  minutes  without  once  hear- 
ing either  trumpets  or  gun ;  nor  had  the  coast-guardsman 
on  duty  heard  any  sound  throughout  the  day.  In  fact,  the 
the  atmosphere  prior  to  the  thunder-storm  was  in  that  floc- 
culent  condition  to  which  I  have  so  often  had  occasion  to 
refer,  being  composed  of  non-homogeneous  locks  of  air  and 
vapor.  The  thunder- storm,  which  I  am  assured  by  Mr. 
Douglass  resembled  the  descent  of  a  water-spout  rather 
than  of  an  ordinary  shower  of  rain,  abolished  this  condition 
of  things,  diminishing  the  partial  echoes,  and  opening  a  freer 
way  for  the  sound  through  the  atmosphere. 

'•In  the  case  of.  Mr.  Ay  res,  the  mastery  of  the  siren  ov 
the  gun  was  very  conspicuous  ;  in  the  case  of  Mr.  Douglass  siren 
also,  though  the  difference  was  not  so  great,  the  siren  was 

heard  a  mile  farther  than  the  gun. 

#  *  *  *  *  *  # 

"  October  31. — *  *  *  This  was  an  exceedingly  thick 
and  squally  day,  with  dense  clouds  and  vapor  everywhere. 
In  acoustic  opacity  it  was  almost  a  match  for  the  memo- 
rable 3d  of  July. 

u  Steamed  with  a  view  of  getting  dead  to  windward  of 
station.  The  siren  was  clearly  heard  through  all  noises. 
During  one  particularly  heavy  squall,  when  the  wind  rose 
to  a  force  of  8,  the  siren  sent  us  a  forcible  sound,  the  horns 

at  the  same  time  being  quite  inaudible. 

*  *  *  *  *  #  * 

"  November  21. — *     *     *     The  result  of  the  day's  obser-    Resuft  of  di- 
vations  was  to  prove  that  the  siren  suffered  far  more  in 
being  directed  from  us  than  the  gun ;    this  means  that 8e 
the  conical  trumpet  associated  with  the  siren  is  far  more 
effectual  in  gathering  up  the  sound  and  sending  it  in  the 
direction  of  the  axis  than  is  the  cylinder  of  the  gun. 

"  The  siren,  pointed  on  us,  was  heard  to-day  through  the 
paddle  noises  at  a  distance  of  five  miles. 

"  We  made  various  observations  in  the  sound-shadow  and 
near  it.  The  fluctuations  in  the  strength  of  the  sound  in- 
dicated that  we  were  passing  through  spaces  of  interference, 
the  sound  being  sometimes  suddenly  augmented  and  some- 
times suddenly  deadened. 

******* 

"  In  the  neighborhood  of  an  acoustic  shadow — we  need 
not  be  in  the  shadow— and  with  a  wind  of  a  force  of  4  tic 
against  the  sound,  there  are  states  of  the  atmosphere  in 
which  even  the  siren  with  its  axis  pointed  on  the  observer 
could  not  be  trusted  for  a  distance  of  one  and  a  half  miles. 


42  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Horns,  whistles,  and  guns,  under  those  circumstances,  are 

simply  nowhere. 

*  *  *  * .  *  *  * 

General  re-  «^_  brief  review  of  our  proceedings  will  aid  the  memory  of 
the  reader  who  has  taken  the  trouble  of  going  over  the  fore- 
going pages.  Daboll's  horn  had  been  highly  spoken  of  by 
writers  on  fog-signals.  A  third-order  apparatus  of  the  kind 
has  been  reported  as  sending  its  sound  to  a  distance  of  from 
seven  to  nine  miles  against  the  wind,  and  to  a  distance  of 
twelve  to  fourteen  miles  with,  the  wind.  Holmes  had  im- 
proved upon  Daboll,  and  with  an  instrument  of  Holmes  of 

mentmmence  ^ne  ^rs^  or(^er  our  experiments  were  made.  They  began  on 
the  19th  of  May,  1873.  Whistles  were  also  employed  on  this 
occasion,  but  those  tested  were  speedily  put  out  of  court. 

u8eTeheistlesfound  At  a  distance  of  two  miles  from  the  Foreland  they  became 
useless.  At  three  miles'  distance  the  horns  also  became 
useless.  At  a  distance  of  four  miles,  with  paddles  stopped 
Gun  effective,  and  all  on  board  quiet,  they  were  wholly  unheard.  The  12 
o'clock  gun  fired  with  a  1-pound  charge  at  the  Drop  Fort  in 
Dover  was  well  heard  on  May  19,  when  the  horns  and 
whistles  were  inaudible.  On  this  first  day  we  noticed  the 
sudden  and  surprising  subsidence  of  the  sound  as  we  ap- 
proached the  acoustic  shadow  lying  beyond  the  line  joining 
the  end  of  the  Admiralty  pier  and  the  South  Foreland.  On 
the  20th  of  May  the  permeability  of  the  atmosphere  by  sound 
had  somewhat  increased,  but  the  steam-whistle  failed  to 
pierce  it  to  a  depth  of  three  miles.  At  four  miles  the 
horns,  though  aided  by  quietness  on  board,  were  barely 
heard.  By  careful  nursing,  if  I  may  use  the  expression,  the 
horn-sounds  were  carried  to  a  distance  of  six  miles.  The 
superiority  of  the  18-pounder  gun,  already  employed  by  the 
Trinity  House,  over  horns  and  whistles,  was  on  this  day  so 
decided  as  almost  to  warrant  its  recommendation  to  the 
exclusion  of  all  the  other  signals. 

" Nothing  occurred  on  the  2d  of  June  to  exalt  our  hopes 
of  the  trumpets  and  whistles.  The  horns  were  scarcely 
heard  at  a  distance  of  three  miles ;  sometimes,  indeed,  they 
failed  to  be  heard  at  two  miles.  By  careful  nursing, 
keeping  everything  quiet  on  board,  they  were  afterward 
carried  to  a  distance  of  six  miles.  Long  previously  they 
had  ceased  to  be  of  use  as  fog-signals.  Considering  the 
demands  as  to  sound-range  made  by  writers  on  this  subject, 
the  demonstrated  incompetence  of  horns  and  whistles  of 
great  reputed  power  to  meet  these  demands  was  not  encour- 
aging. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  43 

"  On  the  3d  of  June  the  atmosphere  had  changed  sur-  June 3,  acoustic 
prisingly.  It  was  loaded  overhead  with  clouds  of  a  dark 
and  threatening  character ;  the  sounds,  nevertheless,  were 
heard  at  a  distance  of  three  and  three-fourths  miles  through 
the  paddle-noises,  while  with  quietness  on  board  they  were 
heard  beyond  nine  miles. 

"On  June  10  the  acoustic  transparency  of  the  air  was 
also  very  fair,  the  distance  penetrated  being  upward  of  eight 
and  three-fourths  miles.  A  large  horn  employed  on  this 
day  was  heard  at  a  distance  of  five  miles  through  the  pad- 
dle-noises. The  subsidence  of  the  sound  near  the  boundary 
of  the  acoustic  shadow  on  the  Dover  side  of  the  Foreland 
was  to-day  sudden  and  extraordinary,  affecting  equally  both 
horns  and  guns.  We  were  warned  to-day  that  the  suprem-  Supremacy  of 

,  ,.     ,     .,     gun  not  invaria- 

acy  of  the  gun  on  one  occasion  by  no  means  implied  itsbie. 
supremacy  on  all  occasions ;  the  self-same  guns  which  on  the 
20th  had  so  far  transcended  the  horns,  being  to-day  their 
equals  and  nothing  more. 

"  The  llth  of  June  was  employed  in  mastering  still  fur- 
ther the  facts  relating  to  the  subsidence  of  the  sound  east 
and  west  of  the  Foreland,  the  cause  of  this  subsidence 
being  in  part  due  to  the  weakening  of  the  sonorous  waves 
by  their  divergence  into  the  sound-shadow,  and  in  part,  no 
doubt,  to  interference. 

"  The  atmosphere  on  the  25th  of  June  was  again  very 
defective  acoustically.  The  sounds  reached  a  maximum  dis- 
tance of  six  and  a  half  miles.  But  at  four  miles,  on  returning 
from  the  maximum  distance,  the  sound  was  very  faint.  The 
guns  to-day  lost  still  further  their  pre-eminence ;  at  five  and  a  Guns  inferior. 
half  miles  their  reports  were  inferior  to  the  sound  of  the 
horn.  No  sounds  whatever  reached  Dover  Pier  on  the  llth, 
and  it  was  only  toward  the  close  of  the  day  that  they  suc- 
ceeded in  reaching  it  on  the  25th.  Thus  by  slow  degrees 
the  caprices  of  the  atmosphere  made  themselves  known  to 
us  ;  showing  that  even  within  the  limits  of  a  single  day  the 
air,  as  a  vehicle  of  sound,  underwent  most  serious  variations. 

"  The  26th  of  June  was  a  far  better  day  than  its  predeces- 
sor, the  acoustic  range  being  over  nine  and  one-quarter 
miles.  The  direction  of  the  wind  was  less  favorable  to  the 
sound  on  this  day  than  on  the  preceding  one,  plainly  prov- 
ing that  something  else  than  the  wind  must  play  an  impor- 
tant part  in  shortening  the  sound-range. 

"  On  the  1st  of  July  we  experimented  upon  a  rotating  horn,    Juiy  i,  rotating" 
and  heard  its  direct  or  axial  blast,  which  was  found  to  behorn/ 
the  strongest,  at  a  distance  of  ten  and  one-half  miles.    The 
sounds  to-day  were  also  heard  at  the  Varne  light-ship,  which 


44  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

is  twelve  and  three-quarters  miles  from  the  Foreland.  The 
atmosphere  nad  become  decidedly  clearer  acoustically,  but 
not  so  optically,  for  on  this  day  thick  haze  obscured  the 
white  cliff's  of  the  Foreland.  In  fact,  on  days  of  far  greater 
optical  purity,  the  sound  had  failed  to  reach  one-third  of  the 
distance  attained  to-day.  By  the  light  of  such  a  fact,  any 
attempt  to  make  optical  transparency  a  measure  of  acoustic 
transparency  must  be  seen  to  be  delusive.  On  the  1st  of 
12  inch  Ameri-  July  a  12-inch  American  whistle,  of  which  we  had  heard  a 

can  whistle.  ,  ,  .    .     ,   .      A , 

highly  favorable  account,  was  tried  in  the  place  of  the  12- 
inch  English  whistle ;  but,  like  its  predecessor,  the  perform- 
ance of  the  new  instrument  fell  behind  that  of  the  horns. 
An  interval  of  twelve  hours  sufficed  to  convert  the  acousti- 
cally clear  atmosphere  of  the  1st  of  July  into  an  opaque 
one ;  for  on  the  2d  of  July  even  the  horn -sounds,  with  pad- 
dles stopped  and  all  noiseless  on  board,  could  not  penetrate 
farther  than  four  miles. 

"  Thus  each  succeeding  day  provided  us  with  a  virtually 
new  atmosphere,  clearly  showing  that  conclusions  founded 
upon  one  day's  observations  might  utterly  break  down  in 
the  presence  of  the  phenomena  of  another  day.  This  was 
most  impressively  demonstrated  on  the  day  now  to  be  refer- 
red to.  The  acoustic  imperviousuess  of  the  3d  of  July  was 
found  to  be  still  greater  than  that  of  the  2d,  while  the  opti- 
cal purity  of  the  day  was  sensibly  perfect.  The  cliffs  of  the 
Extraordinary  Foreland  could  be  seen  to-day  at  ten  times  the  distance  at 

acoustic   opacity          .  .. 

with  optical  which  they  ceased  to  be  visible  on  the  1st,  while  the  sounds 
were  cut  off  at  one-sixth  of  the  distance.  At  2  p.  m.  neither 
guns  nor  trumpets  were  able  to  pierce  the  transparent  air  to 
a  depth  of  three,  hardly  to  a  depth  of  two  miles.  This  ex- 
traordinary opacity  was  proved  to  arise  from  the  irregular 
admixture  with  the  air  of  the  aqueous  vapor  raised  by  a 
powerful  sun. 

"This  vapor,  though  perfectly  invisible,  produced  what 

I  have  called  an  acoustic  cloud  impervious  to  the  sound,  and 

from  which  the  sound-waves  were  thrown  back  as  the  waves 

of  light  are  from  an  ordinary  cloud.    The  waves  thus  refused 

Echoes     from  transmission  produced  by  their  reflection  echoes  of  extraor- 

transparent  air.  djnary  strength  and  duration.  This  I  may  remark  is  the 
first  time  that  audible  echoes  have  been  proved  to  be  reflected 
from  an  optically  transparent  atmosphere.  By  the  low- 
ering of  the  sun  the  production  of  vapor  was  checked,  and 
the  transmissive  power  of  the  atmosphere  restored  to  such 
an  extent  that,  at  a  distance  of  two  miles  from  the  Foreland, 
at  7  p.  m.  the  intensity  of  the  sound  was  at  least  thirty-six 
times  its  intensity  at  2  p.  m.  Nothing  requiring  any  notice 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  45 

here  occurred  cm  July  4,  when  oar  summer  experiments 
ended. 

"On  October  8  the  observations  were  resumed,  a  steain-    Octobers,  ex- 

.  -111perimeut8  re- 

siren  and  a  Canadian  whistle  ot  great  power  being  added  sumcd;  siren. 
to  the  list  of  instruments.  A  boiler  had  its  steam  raised  to 
a  pressure  of  70  pounds  to  the  square  inch.  On  opening  a 
suitable  aperture  this  steam  would  issue  forcibly  in  a  con- 
tinuous stream,  and  the  sole  function  of  the  siren  was  to 
convert  this  stream  into  a  series  of  separate  strong  puffs. 
This  was  done  by  causing  a  disk  with  twelve  radial  slits  to 
rotate  behind  a  fixed  disk  with  the  same  number  of  slits. 
When  the  slits  coincided  a  puff  escaped ;  when  they  did  not 
coincide  the  outflow  of  steam  was  interrupted.  Each  puff 
of  steam  at  this  high  pressure  generated  a  sonorous  wave 
of  great  intensity,  and  the  successive  waves  followed  each 
other  with  such  rapidity  that  they  linked  themselves  together 
to  a  musical  sound  so  intense  as  to  be  best  described  as  a 
continuous  explosion. 

u  During  the  earlier  part  of  October  8  the  optical  trans-    sound    im 
parency  of  the  air  was  very  great;  its  acoustic  transparency, pr 
on  the  other  hand,  was  very  defective.    Clouds  blackened 
and  broke  into  a  rain  and  hail  shower  of  tropical  violence. 
The  sounds,  instead  of  being  deadened,  were  improved  by 
this  furious  squall ;  and,  after  it  had  lightened,  thus  less- 
ening the  local  noises,  the  sound  was  heard  at  a  distance  of 
seven  and  one-half  miles,  distinctly  louder  than  it  had  been 
heard  through  the  preceding  rainless  atmosphere  at  a  dis- 
tance of  five  miles.    Thus  at  five  miles'  distance  the  inten- 
sity of  the  sound  had  been  at  least  doubled  by  the  rain,  a 
result  obviously  due  to  the  removal  by  condensation  and 
precipitation  of  that  vapor,  the  mixture  of  which  with  the 
air  had  been  proved  so  prejudicial  to  fog-signaling.     We   Dependence  be- 
established  this  day  a  dependence  between  the  pitch  of  a  plnetra^pow1 
note  and  its  penetrative  power,  the  siren  generating  480  er> 
waves,  being  slightly  inferior  to  the  horns  5  while  generating 
400  waves  a  second  it  was  distinctly  superior.     The  chaage 
in  the  atmosphere  had  been  one  favorable  to  the  transmission 
of  the  larger  waves.    The  maximum  range  on  October  8  was 
nine  miles.      On  October  9  the  transmissive  power  had 
diminished,  the  maximum  range  being  seven  and  one-half 
miles.    On  both  these  days  the  siren  proved  to  be  superior 
to  the  horns,  and  on  some  occasions  superior  to  the  gun. 

"On  the  10th  and  llth,  our  steamer  having  disappeared,    October  10  and 
we  made  laud-observations.     We  found  the  duration  of  the 
aerial  echoes  to  be  for  the  siren  and  the  gun  9  seconds,  for 
the  horns  6  seconds.    The  duration  varies  from  day  to  day. 


46  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

We  sought  to  estimate  the  influence  of  the  violent  wind 
which  had  caused  our  steamer  to  forsake  us  upon  the  sound, 
and  found  that  the  sound  of  the  gun  failed  to  reach  us  in 

thewSiddSagainsttwo  cases  at  a  distance  of  550  yards  against  the  wind;  the 
sound  of  the  siren  at  the  same  time  rising  to  a  piercing 
intensity.  To  leeward  the  gun  was  heard  at  five  times,  and 
certainly  might  have  been  heard  at  fifteen  times,  the  dis- 
tance attained  to  windward.  The  momentary  character  of 
the  gun-sound  renders  it  liable  to  be  quenched  by  a  single 
puff  of  wind;  but  low  sounds  generally,  whether  momentary 
or  not,  suffer  more  from  an  opposing  wind  than  high  ones. 
We  had  on  the  13th  another  example  of  the  powerlessness 
of  heavy  rain  to  deaden  sound. 

"  On  the  14th  the  maximum  range  was  ten  miles,  but  the 
atmosphere  did  not  maintain  this  power  of  transmission. 
It  was  a  day  of  extreme  optical  clearness,  but  its  acoustic 
clearness  diminished  as  the  day  advanced.  In  fact  the  sun 
was  in  action.  We  proved  to-day  that  by  lowering  the  pitch 
of  the  Canadian  whistle  its  sound,  which  had  previously 
pitch  and  pene- been  inaudible,  became  suddenly  audible.  The  day  at  first 

tration.  wag  favora5ie  to  the  transmission  of  the  longer  sound-waves. 

After  the  lapse  of  three  hours  the  case  was  reversed,  the 
high-pitched  siren  being  then  heard  when  both  gun  and 
horns  were  inaudible.  But  even  this  state  of  things  did 
not  continue,  so  rapid  and  surprising  are  the  caprices  of 
thev atmosphere.  At  a  distance  of  five  miles,  at  3.30  p.  m., 
the  change  in  the  transmissive  power  reduced  the  intensity 
of  the  sound  to  at  least  one-half  of  what  it  possessed  at 
11.30  a.  m.,  the  wind  throughout  maintaining  the  same 
strength  and  direction.  Through  all  this  complexity  the 
knowledge  obtained  on  July  3  sheds  the  light  of  a  principle 
which  reduces  to  order  the  apparent  confusion. 
October  is;  u  October  15  was  spent  at  Dungeness  in  examining  the 

DaboU'shorn.  performance  of  DabolPs  horn.  It  is  a  fine  instrument,  and 
its  application  was  ably  worked  out  by  its  inventor  ;  still  it 
would  require  very  favorable  atmospheric  conditions  to 
enable  it  to  warn  a  steamer  before  she  had  come  danger- 
ously close  to  the  shore.  The  direction  in  which  the  aerial 
echoes  return  was  finely  illustrated  to-day,  that  direction 
being  always  the  one  in  which  the  axis  of  the  horn  is 
pointed. 

October  16;  su-     "  The  16th  was  a  day  of;  exceeding  optical  transparency, 

Sn!lty  °     bebut  of  great  acoustic  opacity.     The  maximum  range  in  the 

axis  was  only  five  miles.     On  this  day  the  howitzer  and  all 

the  whistles  were  clearly  overmastered  by  the  siren.    It 

was,  moreover,  heard  at  three  and  a  half  miles  with  the 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  47 

paddles  going,  while  the  gun  was  unheard  at  two  and  a  half 
miles.  With  no  visible  object  that  could  possibly  yield  an 
echo  in  sight,  the  pure  aerial  echoes,  coming  from  the  more 
distant  southern  air,  were  distinct  and  long-continued  at  a 
distance  of  two  miles  from  the  shore.  Near  the  base  of  the 
Foreland  cliff  we  determined,  their  duration,  and  found  it 
to  be  11  seconds,  while  that  of  the  best  whistle-echoes  was 
6  seconds.  On  this  day  three  whistles,  sounded  simul- 
taneously, were  pitted  against  the  siren,  and  found  clearly 
inferior  to  it.  On  the  17th  four  horns  were  compared  with 
the  siren,  and  found  inferior  to  it.  This  was  our  day  of 
greatest  acoustic  transparency,  the  sound  reaching  a  maxi- 
mum of  fifteen , miles  for  the  siren,  and  of  more  than  six- 
teen for  the  gun.  The  echoes  on  this  day  were  audible  for 
a  longer  time  than  on  any  other  occasion.  They  continued 
for  15  seconds ;  their  duration  indicating  the  atmospheric 
depth  from  which  they  came. 

"On  October  18,  though  the  experiments  were  not  di- 
rected to  determine  the  transmissive-power  of  the  air,  we 
were  not  without  proof  that  it  continued  to  be  high.  From 
10  to  10.30  a.  in.,  while  waiting  for  the  blasts  of  the  siren 
at  a  distance  of  three  miles  from  the  Foreland,  the  contin- 
ued reports  of  what  we  supposed  to  be  the  musketry  of 
skirmishing  parties  on  land  were  distinctly  heard  by  us 
all.  We  afterward  learned  that  the  sounds  arose  from  the  Rifle .  practice 
rifle-practice  on  Kingsdowii  beach,  five  and  a  half  miiesheard5imile8- 
away.  On  July  3,  which,  optically  considered,  was  a  far 
more  perfect  day,  the  18-pounder  howitzer  and  mortar 
failed  to  make  themselves  heard  at  half  this  distance.  The 
18th  was  mainly  occupied  in  determining  the  influence  of 
pitch  and  pressure  on  the  siren-sound,  Taking  the  fluctu- 
ations of  the  atmosphere  into  account,  I  am  of  the  opinion 
that  the  siren,  performing  from  2,000  to  2,400  revolutions 
a  minute,  or,  in  other  words,  generating  from  400  to  480 
waves  per  second,  best  meets  the  atmospheric  conditions. 
We  varied  the  pressure  from  40  to  80  pounds  on  the  square 
inch,  and  though  the  intensity  did  not  appear  to  rise  in 
proportion  to  the  pressure,  the  higher  pressure  yielded  the 
hardest  and  most  penetrating  sound. 

"  The  20th  was  a  raiuv  day  with  a  strong  wind.     Up  to  a    October  ao;  si- 
ren  superior    in 

distance  of  five  and  a  half  miles  the  siren  continued  to  be  rough  weather. 
heard  through  the  sea  and  paddle  noises.  In  rough  weather, 
indeed,  when  local  noises  interfere,  the  siren-sound  far 
transcends  all  other  sounds.  On  various  occasions  to-day 
it  proved  its  mastery  over  both  gun  and  horns.  On  the 
21st,  when  the  deputy  master  paid  us  a  visit,  the  wind  was 


48  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

strong  and  the  sea  high.  The  horn-sounds,  with  paddles 
going,  were  lost  at  four  miles;  the  siren  continued  service- 
able up  to  six  and  a  half  miles.  The  gun  to-day  was  com- 
pletely overmastered.  Its  puffs  were  seen  at  the  Foreland, 
but  its  sound  was  unheard  when  the  siren  was  distinctly 
heard.  Heavy  rain  failed  to  damp  the  power  of  the  siren. 
The  whistles  were  also  tried  to-day,  but  were  found  far  in- 
ferior to  the  siren. 

October  22;  si-  "On  the  22d  it  blew  a  gale,  and  the  Galatea  quitted  us. 
when  local  noises  We  made  observations  on  land  on  the  influence  of  the  wind 
and  of  local  noises.  The  shelter  of  the  coast-guard  station 
at  Cornhill  enabled  us  to  hear  gun-sounds  which  were  quite 
inaudible  to  an  observer  out  of  shelter  5  in^the  shelter  also 
both  horn  and  siren  rose  distinctly  in  power,  but  they  were 
heard  outside  when  the  gun  was  quite  unheard.  As  usual, 
the  sound  to  leeward  was  far  more  powerful  than  those  at 
equal  distances  to  windward.  The  echoes  from  the  cloud- 
less air  were  to-day  very  fine.  On  the  23d,  in  the  absence 
of  the  steamer,  the  observations  on  the  influence  of  the 
wind  were  continued.  The  quenching  of  the  gun-sounds,  in 
particular  to  windward,  was  well  illustrated.  All  the 
sounds,  gun  included,  were  carried  much  farther  to  lee- 

.ward  than  to  windward.     The  effect  of  a  violent  thunder- 
increase  OI 

sound  in  rain,  storm  and  downpour  of  rain  in  exalting  the  sound  was 
noticed  by  the  observers  both  to  windward  and  to  leeward 
of  the  Foreland.  In  the  rear  of  the  siren  its  range  to-day 
was  about  a  mile.  At  right  angles  to  the  axis,  and  to  wind- 
ward, it  was  about  the  same.  To  leeward  it  reached  a  dis- 
tance of  seven  and  one-third  miles. 

"  On  the  24th,  when  observations  were  made  afloat  in  the 
steam  tug  Palmerston,  the  siren  exhibited  a  clear  mastery 
over  gun  and  horns.  The  maximum  range  was  seven  and 
three-quarters  miles.  The  wind  had  changed  from  west- 
southwest  to  southeast,  then  to  east.  As  a  consequence 
of  this  the  siren  was  heard  loudly  in  the  streets  of  Dover. 
On  the  27th  the  wind  was  east-northeast ;  and  the  siren- 
sound  penetrated  everywhere  through  Dover,  rising  over 
the  moaning  of  the  wind  and  all  other  noises.  It  was 
heard  at  a  distance  of  six  miles  from  the  Foreland,  on  the 
road  to  Folkestone,  and  would  probably  have  been  heard 
all  the  way  to  Folkestoce  had  not  the  experiments  ceased. 
Afloat  and  in  the  axis,  with  a  high  wind  and  sea,  the  siren, 
and  it  only,  reached  to  a  distance  of  six  miles  ;  at  five  miles 
'^  was  neard  through  the  paddle-noises.  On  the  28th  fur- 
ther experiments  were  made  on  the  influence  of  pitch  j  the 
siren,  when  generating  480  waves  a  second,  being  found 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  49 

more  effective  than  when  generating  300  waves  a  second.    / 
The  maximum  range  in  the  axis  to-day  was  seven  and  one- 
half  miles. 

"  The  29th  of  October  was  a  day  of  extraordinary  optical 
transparency,  but  by  no  means  transparent  acoustically.  - 
The  gun  was  the  greatest  sufferer.  At  first  it  was  barely 
heard  at  five  miles,  but  afterward  it  was  tried  at  five  and 
one-half,  four  and  one-half,  and  two  and  one-half  miles,  and 
was  heard  at  none  of  these  distances.  The  siren  at  the 
same  time  was  distinctly  heard.  The  sun  was  shining 
strongly,  and  to  its  augmenting  power  the  enfeeblemeut  of 
the  gun-sound  was  probably  due;  wind  from  east-  southeast 
to  east-  northeast.  At  three  and  one-half  miles  subsequently, 
dead  to  windward,  the  siren  was  faintly  heard;  the  gun 
was  unheard  at  two  and  three-fourths  miles.  On  land  Mr. 
Douglass  heard  the  siren  and  horn  sounds  to  windward  at 
two  to  two  and  one-half  miles  ;  to  leeward  Mr.  Edwards 
heard  them  at  seven  miles,  while  Mr.  Ayres,  in  the  rear  of 
the  instruments,  heard  them  inland  at  a  distance  of  five 
miles,  or  five  times  farther  than  they  had  been  heard  on 
October  23. 

"The  30th  of  October  furnished  another  illustration  of   October  30  ;  at 
the  fallacy  of  the  prevalent  notion  which  considers  optical  S 


and  acoustic  transparency  to  go  hand  in  hand.  The  day  r< 
was  very  hazy,  the  white  cliffs  of  the  Foreland  at  the  greater 
distances  being  quite  hidden  ;  still  the  gun  and  siren  sounds 
reached  on  the  bearing  of  the  Varne  light-  vessel  to  a  dis- 
tance of  eleven  and  one-half  miles.  The  siren  was  heard 
through  the  paddle-noises  at  nine  and  one-fourth  miles, 
while  at  eight  and  one-half  miles  it  became  efficient  as  a 
signal  with  the  paddles  going.  The  horns  were  heard  at 
six  and  one-fourth  miles.  This  was  during  calm.  Subse- 
quently, with  a  roaring  wind  from  the  north-northwest,  no 
sounds  were  heard  at  six  and  one-half  miles.  At  South 
Sand  Head  the  siren  was  very  feeble,  the  gun  and  horns 
being  inaudible.  The  wind  was  here  across  the  direction  of 
the  sound.  On  laud,  the  wind  being  also  across,  the  siren 
was  heard  only  to  a  distance  of  three  miles  northeast  of  the 
Foreland;  in  the  other  direction  it  was  heard  plainly  on 
Folkestone  Pier,  eight  miles  distant;  such  was  the  in- 
fluence of  the  wind.  Both  gun  and  horns  failed  to  reach 
Folkestone. 
"Wind,  rain,  a  rough  sea.  and  great  acoustic  opacity  October  31  ;  si- 

J  ren  superior  un- 

charactenzed  October  31.     Both  gun  and  horns  were  un-derveryunfavor- 

,  able  conditions. 

heard  three  miles  away.    The  siren  at  the  same  time  was 
clearly  heard..   It  afterward  forced  its  sound  with  great 
S.  Ex.  54  -  4 


ren 


50  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

s  power  through  a  violent  rain-squall.  Wishing  the  same  in- 
dividual judgment  to  be  brought  to  bear  on  the  sounds  on 
both  sides  of  the  Foreland,  in  the  absence  of  our  steamer, 
which  had  quitted  us  for  safety,  I  committed  the  observa- 
tions to  Mr.  Douglass.  He  heard  them  at  two  miles  on  the 
Dover  side,  and  on  the  Sandwich  side,  with  the  same  in- 
tensity, at  six  miles. 

"A  gap,  employed  by  me  in  preparing  this  report,  and  by 
the  engineers  in  making  arrangements  for  pointing  the 
siren  in  any  required  direction,  here  occurs  in  our  observa- 
tions. They  were,  however,  resumed  on  November  21, 
when  comparative  experiments  were  made  upon  the  gun 
and  siren.  Both  sources  of  sound,  when  employed  as  fog- 
signals,  will  not  unfrequently  have  to  cover  an  arc  of  180°, 
and  it  was  desirable  to  know  with  greater  precision  how 
the  sound  in  windy  weather  is  affected  by  the  direction  in 
which  the  gun  or  siren  is  pointed. 
Effect  of  chang-  <-  The  gun,  therefore,  was  in  the  first  instance  pointed  on 

ing   the   line   of 

direction  of  si-  us  and  fired,  then  turned  and  fired  along  a  line  perpendicu- 
lar to  that  joining  us  and  it.  There  was  a  sensible,  though 
small,  difference  between  the  sounds  which  reached  us  in 
the  two  cases.  A  similar  experiment  was  made  with  the 
siren,  and  here  the  falling  off,  when  the  instrument  was 
pointed  perpendicular  to  the  line  joining  us  and  it,  was  very 
considerable.  This  is  what  is  to  be  expected,  for  the 
trumpet  associated  with  the  siren  is  expressly  intended  to 
gather  up  the  sound  and  project  it  in  a  certain  direction, 
while  no  such  object  is  in  view  in  the  construction  of  the  gun. 
Hence  any  deviation  from  that  direction  must,  in  the  case 
of  the  siren,  be  attended  with  a  greater  weakening  of  the 
sound  than  in  the  case  of  the  gun.  The  experiments  here 
referred  to  were  amply  corroborated  by  others  made  on  No- 
vember 22  and  23. 

"On  both  of  these  days  the  Galatea's  guns  were  fired  both 

Aerial  echoes,  to  wind  ward  and  to  leeward.    The  aerial  echoes  in  the  latter 

case  were  distinctly  louder  and  longer  than  in  the  former. 

"  In  front  of  the  Oornhill  coast-guard  station,  and  only 
one  and  one-fourth  miles  from  the  Foreland,  the  siren,  on 
the  21st,  though  pointed  toward  us,  fell  suddenly  and  con- 
siderably in  power.  Before  reaching  J)over  Pier  it  had 
ceased  to  be  heard.  The  wind  was  here  against  the  sound ; 
but  this,  though  it  contributed  to  the  effect,  could  not  account 
for  it,  nor  could  the  proximity  of  the  shadow  account  for  it.  To 
these  two  causes  must  have  been  added  a  flocculent  atmos- 
phere. The  experiment  demonstrates  conclusively  that 
there  are  atmospheric  and  local  conditions  which  when  coin- 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  51 

bined  prevent  our  roost  powerful  instruments  from  making 
more  than  a  distant  approach  to  the  performance  which 
writers  on  fog-signals  have  demanded  of  them. 

"  On  November  24  the  sound  of  the  siren  pointed  to  co°™gj;f  2ol- 
windward  was  compared  at  equal  distances  in  front  of  and 
behind  the  instrument.  It  was  louder  to  leeward  in  the  rear  of  sound. 
than  at  equal  distances  to  windward  in  front.  Hence  in  a 
wind  the  desirability  of  pointing  the  instrument  to  wind- 
ward. The  whistles  were  compared  this  day  with  the  siren 
deprived  of  its  trumpet.  The  Canadian  and  the  8-inch 
whistles  proved  the  most  effective,  but  the  naked  siren  was 
as  well  heard  as  either  of  them.  As  regards  opacity,  the 
25th  of  November  almost  rivaled  the  3d  of  July.  The  gun 
failed  to  be  heard  at  a  distance  2.8  miles  ;  it  yielded  only  a 
faint  crack  at  two  and  one-half  miles.  This,  as  on  July  3, 
was  when  the  air  was  calm.  A  revival  of  the  wind  subse- 
quently brought  with  it  a  revival  of  the  sound. 

******* 

"  While  the  velocity  of  sound  has  been  the  subjects  of  refined  80Jj^f nsity  of 
and  repeated  experiments,  I  am  not  aware  that  since  the 
publication  of  a  celebrated  paper  by  Doctor  Derham,  in  the  pe?erham'8  pa~ 
Philosophical  Transactions  for  1708,  any  systematic  inquiry 
has  been  made  into  the  causes  which  affect  the  intensity  of 
sound  in  the  atmosphere.  Derham's  results,  though  ob- 
tained at  a  time  when  the  means  of  investigation  were  very 
defective,  have  apparently  been  accepted  with  unquestion- 
able trust  by  all  subsequent  writers;  a  fact  which  is,  I 
think,  in  some  part  to  be  ascribed  to  the  a  priori  probability 
of  his  conclusions. 

"  Thus  Doctor  Robinson,  whom  I  have  already  quoted,   *    *    Dr. 

_  ,  statement. 

relying  apparently  upon  Derham,  says :  '  Fog  is  a  powerful 
damper  of  sound;' and  he  gives  a  physical  reason  why  it 
must  be  so.  '  It  is  a  mixture  of  air  and  globules  of  water,  and 
at  each  of  the  innumerable  surfaces  where  these  two  touch, 
a  portion  of  the  vibration  is  reflected  and  lost.'  And  he  adds 
further  on,  <  The  remarkable  power  of  fogs  to  deaden  the  re- 
port of  guns  has  been  often  noticed.' 

"Assuming  it,  moreover,  as  probable  that  the  measure  of 
1  a  fog's  power  in  stopping  sound'  bears  some  simple  rela- 
tion to  its  opacity  for  light,  Dr.  Robinson,  adopting  a  sug- 
gestion of  Mr.  Alexander  Cunningham,  states  that  'the  dis- 
tance at  which  a  given  object,  say  a  flag  or  pole,  disap- 
pears may  be  taken  as  a  measure  of  the  fog's  power'  to  ob- 
struct the  sound.  This  is  quite  in  accordance  with  prev- 
alent notions,  and,  granting  that  the  sound  is  dissipated, 
as  assumed,  by  reflection  from  the  particles  of  fog,  the  con- 


52  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

elusion  follows  that  the  greater  the  number  of  the  reflecting 
particles  the  greater  will  be  the  waste  of  sound.  But  the 
number  of  particles,  or,  in  other  words,  the  density  of  the 
fog,  is  declared  by  its  action  upon  light  ;  hence  the  optical 
opacity  will  be  a  measure  of  the  acoustic  opacity. 
These  opinions  *«  This  I  say  expresses  the  opinion  generally  entertained  : 

SDOWH  to  be  crro-  j*ii»^i»  -IT 

neous.  <  clear  still  air  '  being  regarded  as  the  best  vehicle  for  sound. 

We  have  not,  as  stated  above,  experimented  in  really  dense 
fogs,  but  the  experiments  that  we  have  made  entirely  de- 
stroy the  notion  that  clear  weather  is  necessarily  better  for 
the  transmission  of  sound  than  thick  weather.  Some  of  our 
days  of  densest  acoustic  opacity  have  been  marvelously 
clear  optically,  while  some  of  our  days  of  thick  haze  have 
shown  themselves  highly  favorable  to  the  transmission  of 
sound.  Were  the  physical  cause  of  the  sound-waves  that 
above  assigned,  did  that  waste  arise  in  any  material  de- 
gree from  reflection  at  the  limiting  surfaces  of  the  particles 
of  haze,  this  result,  as  I  have  already  pointed  out,  would  be 
inexplicable. 

railing  rain  as  "Again,  Derham,  as  quoted  by  Sir  John  Herschel,  says 
that  '  falling  rain  tends  powerfully  to  obstruct  sound.7  We 
have  had  repeated  reversals  of  this  conclusion.  Some  of 
our  observations  have  been  made  on  days  when  rain  and 
hail  descended  with  a  perfectly  tropical  fury,  and  in  no 
single  case  did  the  rain  deaden  the  sound.  In  every  case, 
indeed,  it  had  precisely  the  opposite  effect. 

railing  snow.  <<  But  falling  snow,  according  to  Derham,  offers  a  more  se- 
rious obstacle  than  any  other  meteorological  agent  to  the 
transmission  of  sound.  We  have  not  extended  our  observa- 
tions  at  the  SouthForelaudintosuowy  weather.  But  I  may  be 


the  Merde  Giace.  permitted  to  refer  to  an  observation  of  my  own  which  bears- 
directly  upon  this  point.  On  Christmas  night,  1859,  1  reached 
Chamouni,  through  snow  so  deep  as  to  obliterate  the  road- 
fences.  On  the  26th  and  27th  it  fell  heavily.  During  a  lull 
in  the  storm  I  reached  the  Montanvert,  sometimes  breast- 
deep  in  snow.  On  the  29th  the  entry  in  my  journal  is  i  Snow, 
heavy  snow  ;  it  must  have  descended  through  the  entire 
night,  the  quantity  freshly  fallen  is  so  great.7  Dr.  Derham 
had  referred  to  the  deadening  effect  produced  by  a  coating 
of  fresh-fallen  snow  upon  the  ground,  alleging  that  when 
the  surface  was  glazed  by  freezing  the  damping  of  the  sound 
disappeared. 

"  Well,  on  December  29,  1  took  up  a  position  beside  the 
Mer  de  Glace,  with  a  view  to  determine  its  winter  motion, 
and  sent  my  assistants  across  the  glacier  with  instructions 
to  measure  the  displacement  of  a  transverse  line  of  stakes 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  53 

planted  previously  in  the  snow.  I  was  standing  at  the  time 
beside  my  theodolite,  with  snow  4  feet  deep  around  ine. 
A  storm  drifted  up  the  valley,  darkening  the  air  as  it  ap- 
proached. It  reached  us,  the  snow  falling  more  heavily 
than  ever  I  had  seen  it  elsewhere.  It  soon  formed  a  heap  on 
my  theodolite;  still  through  the  telescope  I  was  able  to 
pick  up  at  intervals  the  retreating  forms  of  my  men.  Here 
there  was  a  combination  of  thick  snow  in  the  air  and  of  soft 
fresh  snow  on  the  ground,  such  as  Derham  had  hardly  en- 
joyed. Through  such  an  atmosphere,  however,  I  was  able  . 
with  my  unaided  voice  to  make  my  instructions  audible  for 
half  a  mile,  while  the  experiment  was  rendered  reciprocal  by 

one  of  my  men  making  his  voice  audible  to  me. 

*  *  *  *  *  *  * 

"  The  real  enemy  to  the  transmission  of  sound  through  neo^s°°aho™0t^6e" 
the  atmosphere  has,  I  think,  been  clearly  revealed  by  the  cause  of  acoustic 
foregoing  inquiry.    That  enemy  has  been  proved  to  be  not  °P 
rain,  nor  hail,  nor  haze,  nor,  I  imagine,  fog  or  snow ;  not 
water,  in  fact,  in  either  a  liquid  or  a  solid  form,  but  water  in 
a  vaporous  form,  mingled  with  air,  so  as  to  render  it  acous- 
tically turbid  and  flocculent.    This  acoustic  turbidity  often 
occurs  on  days  of  surprising  optical  transparency.    Any 
system  of  measures,  therefore,  founded  on  the  assumption 
that  the  optic  and  acoustic  transparency  of  the  atmosphere 
go  hand  in  hand  must  prove  delusive. 

"  There  is  but  one  solution  of  this  difficulty:  it  is  to  make 
the  source  of  sound  so  powerful  as  to  be  able  to  endure  con- 
siderable loss  by  partial  reflection  and  still  retain  a  sufficient 
residue  for  transmission.  Of  all  the  instruments  hitherto  thf"?ren°rity  °f 
examined  by  us  the  siren  comes  nearest  to  the  fulfillment 
of  this  condition.  Its  establishment  upon  our  coast  will,  in 

my  opinion,  prove  an  incalculable  boon  to  the  mariner. 

*  *  ***** 

u  We  had,  as  already  stated,  been  favored  with  thunder,   NO  experiments 
hail,  rain,  and  haze,  but  not  with  dense  fog.    All  the  more  denseefog.ma 
anxious  was  I  to  turn  the  recent  excellent  opportunity  to 
account.    On  Tuesday,  December  9. 1  therefore  telegraphed 
to  the  Trinity  House,  suggesting  some  gun-observations.    A 
prompt  reply  informed  me  that  such  observations  would  be 
made  in  the  afternoon  at  Blackwall  or  in  its  neighborhood. 

*  *  *  *  *  *  * 

"  Slowly,  but  surely,  we  thus  master  this  question.    And    F0gs    do  not 
the  further  we  advance  the  more  we  are  assured  that  our  deaden  80untl- 
reputed  knowledge  regarding  it  has  been  erroneous  from 
beginning  to  end.    Fogs,  like  rain,  have  no  such  power 


54 


EUROPEAN    LIGHT-HOUSE    SYSTEMS, 


Experiments  in 
Hyde  .  irk,  Lon- 


December  si. 


January  22. 


to  deaden  sound  as,  since  the  time  of  Derham,  has  been 

universally  ascribed  to  them. 

#  *  #  *  *  *  * 

"An  assistant  placed  at  the  end  of  the  Serpentine  sounded 
^e  w]1istie  and  pipe  for  fifteen  minutes  without  interrup- 
tion. An  observer  at  the  bridge  noticed  the  fluctuations  of 
the  sound.  Sometimes  the  whistle  was  heard  alone,  some- 
times the  organ-pipe.  Sometimes  both  whistle  and  pipe 
began  strongly  and  ended  by  sinking  almost  to  inaudibility. 
Extraordinary  fluctuations  were  also  observed  in  the  peal 
of  bells,  to  which  reference  has  been  already  made.  In  a 
few  seconds  they  would  sink  from  a  loudly  ringing  peal  into 
utter  silence,  from  which  they  would  rapidly  return  to  loud- 
tougued  audibility.  The  intermittent  drifting  of  fog  over 
the  sun's  disk,  by  which  his  light  is  at  times  obscured,  at 
times  revealed,  is,  as  already  stated,  the  optical  analogue 
of  these  acoustical  effects.  In  fact,  as  regards  such  changes, 
the  acoustic  deportment  of  the  atmosphere  is  a  true  tran- 

script of  its  optical  deportment. 

*  *  *  *  *  *  * 

"  On  December  31  1  went  to  the  end  of  the  Serpentine, 
at  noon,  to  listen  to  the  Westminster  bell.  Not  one  of  the 
twelve  strokes  was  audible,  nor  were  the  chimes  heard.  On 
several  of  the  first  days  of  this  year  I  placed  myself  beside 
the  railing  of  St.  James's  Park,  near  Buckingham  Palace, 
and  waited  at  noon  for  the  stroke  of  the  bell  ;  it  was  quite 
unheard.  These  days  were  moist  and  warm,  the  air  was 
calm,  and  the  clock  -tower  in  sight.  On  January  19  1  placed 
myself  in  the  same  position  ;  fog  and  drizzling  rain  obscured 
the  tower  $  still  I  heard  not  only  the  strokes  of  the  big  bell, 
but  also  the  preceding  chimes  of  the  quarter-bells.  The  air 
was  calm  at  the  time. 

"  During  the  exceedingly  dense  and  <  dripping  '  fog  of  Jan- 
uary 22  I  placed  myself  near  the  same  railings,  and  heard 
every  stroke  of  the  bell.  On  the  same  day  I  sent  an  assist- 
ant to  the  end  of  the  Serpentine,  and  when  the  fog  was 
densest  he  heard  the  Westminster  bell  striking  loudly 
eleven.  Toward  evening  this  fog  began  to  melt  away,  and 
at  6  o'clock  I  went  to  the  end  of  the  Serpentine  to  observe 
the  effect  of  the  clearing  of  the  atmosphere  upon  the  sound. 
Not  one  of  the  strokes  reached  me.  At  9  o'clock,  and  at  10 
o'clock,  my  able  assistant,  Mr.  Cottrell,  was  in  the  same 
position,  and  on  both  occasions  failed  to  hear  a  single  stroke 
of  the  bell.  It  was  a  case  precisely  similar  to  that  of  De- 
cember 13,  when  the  dissolution  of  the  fog  was  accompanied 
by  a  decided  acoustic  thickening  of  the  atmosphere.  All 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  55 

this  shows  what  instructive  results  are  to  be  obtained  in 
connection  with  the  transmission  of  sound  through  the 
atmosphere  from  a  mode  of  observation  accessible  to  all. 

"This  opportune  fog  enabled  us  to  remove  the  last  of  amo^e<Jor8   re" 
congeries  of  errors  which,  ever  since  the  year  1708,  have 
attached  themselves  to  this  question.    As  regards  phonic 
coast- signals,  we  now  know  exactly  where  we  stand;  and, 
through  the  application  of  this  knowledge  to  maritime  pur-        , 
poses,  a  meteorological  phenomenon,  which  was  bewailed 
in  London  as  an  unmitigated  evil,  may  in  the  end  redound 
to  the  advantage  of  the  public. 

"  Since  the  publication  of  the  first  notices  of  this  investi-    Portland  guns 
gation  various  communications  have  reached  me,  to  one  or  SSies  f°through 
two  of  which  I  should  like  to  refer.    The  Kev.  George  H.densefog 
Hetling,  of  Fulham,  has  written  to  me  with  a  circumstan- 
tiality which  leaves  no  room  for  doubt,  that  he  has  heard 
the  Portland  guns  at  a  distance  of  forty-four  miles  through 
a  dense  fog. 

"The  Duke  of  Argyll  has  also  favored  me  with  the  fol-    statement    of 

,  „  ,  .  .  !n        •  .^i          tho  Duke  of  Ar- 

lowmg  account  of  his  own  experience.  Coming  as  it  does  gyii. 
from  a  disciplined  scientific  observer,  it  is  particularly  val- 
uable. i  This  fact  [the  permeability  of  fog  by  sound]  I 
have  long  known,  from  having  lived  a  great  part  of  my  life 
within  four  miles  of  the  town  of  Greenock,  across  the  Frith. 
Ship-building  goes  on  there  to  a  great  extent,  and  the  ham- 
mering of  the  calkers  and  builders  is  a  sound  which  I  have 
been  in  the  habit  of  hearing  with  every  variety  of  distinct- 
ness, or  of  not  hearing  at  all,  according  to  the  state  of  the 
atmosphere ;  and  I  have  always  observed  on  days  when  the 
air  was  very  clear,  and  every  mast  and  spar  was  distinctly 
seen,  hardly  any  sound,  was  heard,  whereas  on  thick  and 
foggy  days,  sometimes  so  thick  that  nothing  could  be  seen, 
every  clink  of  every  hammer  was  audible  and  appeared 
sometimes  as  close  at  hand.  This  has  been  long  a  very 
familiar  experience  with  me.7 

"It  is  hardly  necessary  for  me  to  say  a  word  to  guard    The  real  bar- 
inyself  against  the  misconception  that  I  consider  sound  toSon.to 
be  assisted  by  the  fog  itself.    Fog  I  regard  as  the  visible 
result  of  an  act  of  condensation,  which  removes  the  real 
barrier  to  transmission,  that  barrier  being  aqueous  vapor 
so  mixed  with  air  as  to  render  it  acoustically  fiocculent  or 
turbid.    The  fog-particles  appear  to  have  no  more  influence 
upon  the  waves  of  sound  than  the  suspended  matter  stirred 
up  over  the  banks  of  Newfoundland  has  upon  the  waves  of 
the  Atlantic. 


56  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

superiority  of  "Ail  absolutely  uniform  superiority  on  all  days  cannot  be 
conceded  to  any  one  of  the  instruments  subjected  to  exami- 
nation 5  still,  our  observations  have  been  so  numerous  and 
long-continued  as  to  enable  us  to  come  to  the  sure  conclu- 
sion that,  on  the  whole,  the  steam-siren  is  beyond  question 
the  most  powerful  fog-signal  which  has  hitherto  been  tried 
in  England.  It  is  specially  powerful  when  local  noises, 
^  such  as  those  of  wind,  rigging,  breaking  waves,  shore-surf, 
and  the  rattle  of  pebbles  have  to  be  overcome.  Its  density, 
quality,  pitch,  and  penetration  render  it  dominant  over  such 
noises  after  all  other'signal-sounds  have  succumbed. 

"  I  do  not  hesitate  to  recommend  the  introduction  of  the 
siren  as  a  coast-signal. 
change    in     "  It  will  be  desirable  in  each  case  to  confer  upon  the  in- 

Srabu?  sir6n  strurnent  a  power  of  rotation,  so  as  to  enable  the  person  in 
charge  of  it  to  point  its  trumpet  against  the  wind,  or  in  any 
other  required  direction.  This  arrangement  has  been  made 
at  the  South  Foreland,  and  it  presents  no  mechanical  diffi- 
culty. It  is  also  desirable  to  mount  the  siren  so  as  to  per- 
mit of  the  depression  of  its  trumpet  15°  or  20°  below  the 
horizon. 
Position  of  fog-  "  I*1  selecting  the  position  at  which  a  fog-signal  is  to  be 

signal.  mounted,  the  possible  influence  of  a  sound-shadow,  and  the 

possible  extinction  of  the  sound  by  the  interference  of  the 
direct  waves  with  waves  reflected  from  the  shore,  must  form 
the  subject  of  the  gravest  consideration.  Preliminary  trials 
may  in  most  cases  be  necessary  before  fixing  on  the  precise 

point  at  which  the  instrument  is  to  be  placed. 

' 


siren,  with     u  ^ne  form  of  the  siren  which  has  been  longknown  to  sci- 

compressed  air.   entific  men  is  worked  with  air,  aucVit  would  be  worth  while 

to  try   how  the  fog-siren  would    behave  supposing  com- 

pressed air  to  be  substituted  for  steam.    Compressed  air 

might  also  be  tried  with  the  whistles. 

Robinson's  "  ^°  fog-signal  hitherto  tried  is  able  to  fulfill  the  condi- 
fuimied^by  ann°y  tio11  laid  d°wn  by  I>r-  Robinson,  *  *  *  namely.  '  that  all 
fog-signal.  fog-signals  sliould  ~be  distinctly  audible  for  at  least  four  miles 
under  every  circumstance.'  Circumstances  may  arise  to  pre- 
vent the  most  powerful  sounds  from  being  heard  at  half 
this  distance.  What  may  with  certainty  be  affirmed  is,  that 
in  almost  all  cases  the  siren,  even  on  steamers  with  paddles 
going,  may  be  relied  on  at  a  distance  of  two  miles  ;  in  the 
great  majority  of  cases  it  may  be  relied  upon  at  a  distance 
of  three  miles,  and  in  the  majority  of  cases  at  a  distance 
greater  than  three  miles. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  57 

"  Happily,  the  experiments  thus  far  made  are  perfectly  ejjjg|j£8 
concurrent  in  indicating  that  at  the  particular  time  when  fog. 
fog-signals  are  needed,  that  is,  during  foggy  weather,  the 
air  in  which  the  fog  is  suspended  is  in  a  highly  homogeneous 
condition  $  hence  it  is  in  the  highest  degree  probable  that 
in  the  case  of  fog  we  may  rely  upon  these  signals  being 
effective  at  much  greater  distances  than  those  just  men- 
tioned. 

"  I  say  i  probable,'  while  the  experiments  seem  to  render 
this  result  certain.  Before  pronouncing  it  so,  however,  I 
should  like  to  have  some  experience  of  warmer  fogs  than 
those  in  which  the  experiments  have  hitherto  been  made. 
That  the  fog- particles  themselves  are  not  sensibly  injurious 
to  the  sound  has  been  demonstrated ;  but  it  is  just  possible 
that  in'  warm  weather  the  air  associated  with  the  fog  may 
not  be  homogeneous.  I  would  recommend  the  experiment 
necessary  to  decide  this  point  to  be  made  on  some  of  the 
fogs  of  the  early  summer. 

"I  am  cautiousnot  to  inspire  the  mariner  with  a  confidence    Distance  at 

-r-i-r,          ,        -,  f,  •          T  i       which    a    signal 

which  may  prove  delusive.    When  he  hears  a  tog-signal  he  should  be  heard, 
ought,  as  a  general  rule,  at  all  events  until  extended  expe- 
rience justifies  the  contrary,  to  assume  the  source  of  sound 
to  be  not  more  than  two  or  three  miles  distant,  and  to  take 
precautions  accordingly. 

"Once  warned,  he  may,  by  the  heaving  of  the  lead  or 
some  other  means,  be  enabled  to  check  his  position.  But 
if  he  errs  at  all  in  his  estimate  of  distance,  it  ought  to  be  on 
the  side  of  safety.  . 

"  Unless  very  cogent  practical  reasons  can  be  adduced  in    intervals    be- 
tween blasts, 
its  favor,  I  should  strongly  deprecate  a  lengthened  interval 

between  the  siren-blasts.  My  own  small  experience  has 
shown  me  how  harassing  to  the  mariner  are  some  of  our 
revolving  lights  with  a  long  period  of  rotation.  'No  light, 
in  my  opinion,  ought  to  be  obscured  for  more  than  30  sec- 
onds, and  the  interval  between  the  two  blasts  of  our  fog- 
signal  ought  not  to  be  longer. 

"With  the  instruments  now  at  our  disposal,  wisely  estab- 
lished along  our  coasts,  1  venture  to  believe  that  the  saving 
of  property  in  ten  years  will  be  an  exceedingly  large  mul- 
tiple of  the  outlay  necessary  for  the  establishment  of  such 
signals.  The  saving  of  life  appeals  to  the  higher  motives 
of  humanity." 

*  *=  *  #  #          #  # 

General  Duane,  of  the  Corps  of  Engineers  of  the  Army    Report     from 
and  light-house  engineer  of  the  New  England  coast,  for-  G 
warded  to  the  Light- House  Board  on  January  12,  1872,  a 


58  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

report  which  corroborates  the  results  of  Professor  TyudalFs 
experiments,  some  of  which  were  foreshadowed  iri  his  treatise 
on  Sound,  published  in  '1867.  This  report  contains  much 
practical  information  in  regard  to  fog-signals,  and  it  is  to 
be  regretted  that  it  has  not  been  published.  The  following 
are  extracts  from  General  Duane's  report: 

******* 

Fog-signais  on     "  There  are  six  steam  fog-  whistles  on  the  coast  of  Maine. 

the,  Maine  coast.  Tliese  nave  beeu  frequently  heard  at  a  distance  of  twenty 

miles,  and  as  frequently  cannot  be  heard  at  the  distance  of 

two  miles,  and  this  with  no  perceptible  difference  in  the 

state  of  the  atmosphere. 

signal  some-  "  The  signal  is  often  heard  at  a  great  distance  in  one 
in™nse  tocS?  direction,  while  in  another  it  will  be  scarcely  audible  at  the 
distance  of  a  mile.  This  is  not  the  effect  of  wind,  as  the 
signal  is  frequently  heard  much  farther  against  the  wind 
than  with  it.  For  example,  the  whistle  on  Cape  Elizabeth 
can  always  be  distinctly  heard  in  Portland,  a  distance  of 
nine  miles,  during  a  heavy  snow-storm,  the  wind  blowing  a 
gale  directly  from  Portland  toward  the  whistle. 

Beit    impene-      "The   most  perplexing  difficulty,  however,  arises  from 
Soundin^he  the  fact  that  the  signal  often  appears  to  be  surrounded  by 
a  belt,  varying  in  radius  from  one  to  one  and  a  half  miles, 
from  which  the  sound  appears  to  be  entirely  absent. 
sound  lost  for     "  Thus,  in  moving  directly  from  a  station,  the  sound  may 
thence  audible  for  the  distance  of  a  mile,  is  then  lost  for  about 


the  same  distance,  after  which  it  is  again  distinctly  heard 
for  a  long  time.  This  action  is  common  to  all  ear-signals, 
and  has  been  at  times  observed  at  all  the  stations,  at  one 
of  which  the  signal  is  situated  on  a  bare  rock  twenty  miles 
from  the  main-land,  with  no  surrounding  objects  to  affect 
the  sound.  All  attempts  to  re  enforce  the  sound  by  means 
of  reflectors  have  hitherto  been  unsuccessful.  Upon  a 
large  scale  sound  does  not  appear,  on  striking  a  surface,  to 
be  reflected  after  the  manner  of  light  and  heat,  but  to  roll 

along  it  like  a  cloud  of  smoke. 

*  *  *  *  *  *  * 

"  -^rom  au  attentive  observation  during  three  years  of  the 
fog-signals  on  this  coast,  and  from  the  reports  received 
from  captains  and  pilots  of  coasting-vessels,  I  am  convinced 
that  in  some  conditions  of  the  atmosphere  the  most  power- 

ful signals  will  be  at  times  unreliable. 

*  *****  * 

Reflection  at-  "  ]STow,  it  frequently  occurs  that  a  signal,  which  under  or- 
dinary circumstances  would  be  audible  at  the  distance  of 
fifteen  miles,  cannot  be  beard  from  a  vessel  at  the  distance 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  59 

of  a  single  mile.  This  is  probably  due  to  the  reflection 
mentioned  by  Humboldt. 

"  The  temperature  of  the  air  over  the  land  where  the  fog- 
signal  is  located  being  very  different  from  that  over  the 
sea,  the  sound,  in  passing  from  the  former  to  the  latter, 
undergoes  reflection  at  their  surfaces  of  contact.  The  cor- 
rectness of  this  view  is  rendered  more  probable  by  the  fact 
that  when  the  sound  is  thus  impeded  in  the  direction  of  the 
sea,  it  has  been  observed  to  be  much  stronger  inland. 

"  When  a  vessel  approaches  a  signal  in  a  fog  a  difficulty    Difficulty     in 

.  determining  posi- 

is  sometimes  experienced  in  determining  the  position  of  the  tion of  the  signal, 
signal  by  the  direction  from  which  the  sound  appears  to 
proceed,  the  apparent  and  true  direction  being  entirely 
different.    This  is  undoubtedly  due  to  the  refraction  of 
sound  passing  through  media  of  different  density. 

"  Experiments  and  observation  lead  to  the  conclusion    Reason  for  the 
that  these  anomalies  in  penetration  and  direction  of  sound  to  exist** 
from  fog-signals  are  to  be  attributed  mainly  to  the  want  of 
uniformity  in  the  surrounding  atmosphere,  and  that  snow, 
rain,  fog,  and  the  force  and  direction  of  the  wind  have  much 
less  influence  than  has  generally  been  supposed." 


While  this  report  is  passing  through  the  press,  Sir  Fred- 
erick has  also  kindly  sent  me  a  copy  of  his  memorandum  to 
the  Elder  Brethren  of  the  Trinity  House  concerning  the  re- 
port of  Professor  Tyndall,  and  it  will  be  found  below. 


MEMORANDUM  BY  SIR  FREDERICK  ARROW,  THE  DEPUTY 
MASTER  OF  THE  TRINITY  HOUSE,  UPON  DR.  TYNDALI/S 
REPORT  ON  THE  EXPERIMENTS  AT'  SOUTH  FORELAND. 


"At  the  close  of  a  series  of  important  investigations, 
undertaken  with  the  desire  of  adding  to  the  safety  of  navi- 
gation round  our  seaboard,  to  which  a  committee  of  the 
Elder  Brethren,  acting  in  concert  with  the  corporation's 
scientific  adviser,  have  devoted  many  months  of  careful 
attention,  it  will  be  convenient,  now  that  the  report  of  Dr. 
Tyndall  has  been  presented  to  the  board,  to  consider  how 
far  the  conclusions  arrived  at  may  be  practically  and  use 
fully  applied. 

u  Before  entering,  however,  upon  the  subject-matter  of  the 
report,  it  is  due  to  the  members  of  the  committee,  who  have 
freely  sacrificed  their  time  and  comfort  during  a  protracted 
period,  that  the  board  should  record  its  acknowledgment 
of  their  careful  prosecution  of  a  long  and  arduous  duty. 


60  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

And  if  this  acknowledgment  is  due  .to  the  members  of  the 
committee,  much  more  is  to  be  accorded  to  their  distin- 
guished scientific  guide,  Dr.  Tyndall,  who  at  great  incon- 
venience to  himself,  with  serious  encroachment  on  his  valu- 
able time,  and  frequently  some  personal  discomfort,  has 
applied  himself  to  this  investigation  with  characteristic 
patience  and  perseverance.  Step  by  step,  after  repetitions 
almost  wearying  to  those  unversed  in  such  trained  and  dis- 
passionate habits  of  procedure,  the  conditions  affecting  the 
traveling-power  of  sound  have  become  clearer  and  clearer, 
old  errors  have  been  corrected,  and  a  great  advance  has 
been  made  toward  accurately  estimating  the  value  of  sound- 
signals;  and  the  important  knowledge  has  been  acquired 
that  the  seaman's  greatest  enemy  affords  in  itself  aid  to 
mitigate  its  worst  evils. 

"  To  Mr.  Douglass  also  and  his  assistants  much  credit  is 
due  for  the  very  thorough  and  efficient  manner  in  which 
they  performed  their  duties  in  connection  with  this  inquiry, 
and  Mr.  Douglass's  assistance  as  a  practical  observer  on 
board  the  yachts  has  throughout  the  experiments  been  of 
great  service. 

u  Observations  at  sea  were  commenced  on  the  19th  of 
May,  1873,  after  some  months  previously  employed  by  the 
engineering  department  in  mounting  the  requisite  instru- 
ments, (the  selection  of  which  was  based  upon  the  report  of 
the  committee  who  had  visited  the  fog-signal  establishments 
of  the  North  American  seaboard,)  and  in  making  such 
arrangements  as  were  suggested  by  the  experience  of  the 
Elder  Brethren  and  Mr.  Douglass  or  by  the  views  of  Dr. 
Tyndall  on  the  subject.  From  that  time  to  the  21st  of  Feb- 
ruary, 1874,  on  shore  and  at  sea  the  observations  have  been 
going  on  at  short  intervals,  and  frequently  for  weeks 
together. 

"  Foremost  among  the  practical  results  is  the  important 
fact  before  alluded  to,  viz,  that  fog  does  not  impede  the 
transmission  of  sound,  (as  has  long  been  supposed ;)  indeed, 
it  is  shown  that  a  foggy  atmosphere  is  a  highly  favorable 
condition  for  the  traveling  of  the  sound-wave;  further, 
during  heavy,  blinding  rain  or  snow  storms  the  passage 
of  sound  through  the  air  is  not  obstructed ;  indeed,  the 
observations  of  the  committee  in  the  former  case  record  an 
increase  in  the  power  of  the  sound  either  during  or  immedi- 
ately after  a  rain-storm ;  while  the  evidence  of  Dr.  Tyndall 
of  his  Alpine  experience  with  regard  to  falling  snow  may  be 
accepted  as  proving  the  latter.  It  may  safely  be  concluded, 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  61 

therefore,  that  whenever  the  state  of  the  weather  is  such  as 
to  render  sound- signals  necessary,  the  atmospheric  condi- 
tions are  most  favorable  for  their  efficient  application,  and 
it  may  also  be  concluded  that,  under  the  conditions  of 
weather  above  referred  to,  the  range  of  the  signals  will  be 
much  greater  than  the  limit  laid  down  in  the  report  as  the 
result  of  the  general  observations. 

"Turning  to  the  action  of  the  wind  upon  sound,  the  report 
confirms  all  previous  experience,  and  shows  that  the  most 
powerful  sound  fails  to  penetrate  the  opposing  force  of  a 
strong  wind  to  any  considerable  distance ;  but  it  is  satis 
tory  to  be  assured  that  even  against  a  moderate  gale  and 
unfavorable  conditions  for  sound-transmission  signals  may 
be  relied  on  for  sending  sound  to  a  distance  of  two  or  three 
miles,  and,  under  ordinary  conditions  of  fog,  considerably 
farther.  Having  regard,  howrever,  to  the  variability  of  the 
sound-range  of  the  same  instrument  on  different  days, 
attributable  to  the  varying  conditions  of  the  atmosphere,  it 
is  not  possible  to  assert  positively  that  any  signal  has  an 
absolute  range  which  may  be  relied  upon  at  all  times.  The 
practice  of  the  Elder  Brethren  of  not  publishing  in  their 
notices  of  fog-signals  a  maximum  range  of  audibility,  or  of 
accepting  isolated  instances  as  every-day  occurrences,  is 
therefore  amply  justified.  Happily  long  ranges  are  not 
very  necessary,  inasmuch  as  the  mariner  does  not  need  to 
hear  a  sound-signal  at  ten,  fifteen,  qr  twenty  miles.  Dr. 
Tyndall  quotes,  in  relation  to  this  part  of  the  subject,  an 
opinion  expressed  by  our  late  scientific  adviser,  Professor 
Faraday,  that  4a  false  promise  to  the  mariner  would  be 
worse  than  no  promise  at  all.'  The  Brethren  need  scarcely 
be  reminded  that  in  so  saying  our  dear  and  venerated  friend 
was  simply  giving  utterance  to  the  standard  axiom  of  the 
Trinity  House,  as  old,  perhaps,  as  the  corporation  itself, 
viz,  that  safety  is  only  to  be  found  in  certainty,  and  that 
anything  which  does  not  secure  the  latter  condition  is  a 
foe,  rather  than  a  friend,  to  the  mariner. 

u  Bearing  in  mind,  therefore,  the  liability  to  atmospheric 
interference  under  ever-varying  conditions,  as  shown  in  the 
report,  attention  must  next  be  directed  to  the  instruments 
used  in  the  investigation  and  the  conclusions  arrived  at 
with  regard  to  each  of  them,  so  far  as  the  inquiry  has  now 
advanced. 

"  The  instruments  tried  were  the  American  siren,  Holmes's 
trumpets,  American,  Canadian,  and  English  steam-whistles, 
and  three  guns.  The  effects  obtained  from  all  these  instru- 
ments have  varied  in  a  remarkable  manner  at  different 


62  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

times,  but  for  general  efficiency  there  is  no  doubt  that  the 
American  siren  takes  the  first  place.  It  has  shown  the 
greatest  penetrative  power,  especially  where  local  noises 
have  to  be  overcome,  but  at  present  it  has  the  drawback  of 
being  worked  by  steam  at  the  high  pressure  of  70  pounds, 
which  is  not  only  a  serious  element  of  danger,  but  entails 
considerable  expense  for  fuel  and  labor.  Mr.  Douglass, 
however,  tells  us  that  the  caloric-engine  will  work  the  siren, 
and  he  confidently  anticipates  being  able  to  do  away  with 
steam  altogether,  and  so  to  render  this  instrument  a  safe, 
economical,  and  efficient  signal  for  general  adoption. 

"  The  air-trumpet  has  also  shown  itself  to  be  an  efficient 
instrument,  superior  to  the  whistles  and  sometimes  equal- 
ing the  siren.  Its  chief  advantage  is  that  it  is  blown  by 
means  of  the  caloric-engine  at  something  over  20  pounds7 
pressure,  and  can  be  worked  without  skilled  labor,  and, 
avoiding  the  danger  attendant  upon  the  employment  of 
steam  or  gunpowder,  combines  safety  with  economy  ;  and 
its  clear,  musical  note  may  be  an  element  of  distinctiveness 
capable  of  being  developed  so  as  to  make  it  ultimately  of 
some  service  in  this  respect.  In  actual  practice  there  are 
one  or  two  drawbacks  to  the  use  of  reed-instruments,  such 
as  the  difficulty  of  tuning,  liability  of  reeds  cracking,  &c. 
Such  contingencies  are  not  likely  to  arise  in  regard  to  the 
siren,  and  if  the  economy  and  simplicity  of  working  by 
means  of  the  caloric-engine  can  be  also  applied  to  the  more 
powerful  siren,  it  seems  clear  that  the  result  will  be  highly 
advantageous  as  a  most  useful  combination  of  power,  safety, 
and  economy  well  suited  for  fog-signal  purposes.  Never- 
theless the  satisfactory  performance  of  the  trumpets  during 
the  late  trials  fully  justifies  their  present  employment  as 
fog-signals. 

"  Not  so  much  can  be  said  in  favor  of  whistles.  Through- 
out the  trials  their  marked  inferiority  to  the  other  instru- 
ments has  been  recorded.  The  American  whistle,  yielding 
a  harsh  roar,  when  close  at  hand  was  deafening,  but  its 
sound  failed  to  penetrate  to  any  useful  distance.*  The  Ca- 
nadian whistle  appears  to  have  been  better,  but  it  also 
failed  in  general  effective  power,  although  occasionally  it 
was  heard  a  great  distance,  even  obtaining  superiority  over 
the  other  instruments,  but  this  was  of  very  rare  occurrence. 
As  a  rule,  the  whistles  were  behind  the  siren,  trumpet,  and 
gun,  and  seem  to  have  been  dependent,  more  than  the  other 
instruments,  on  exceptional  atmospheric  conditions  for 

*  This  statement  does  not  agree  with  our  experience  in  the  practical 
use  of  a  large  number  of  steam  fog-whistles  on  the  seacoast  of  the  United 
States.— E. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  63 

yielding  their  best  results.  The  general  conclusion  seems 
to  be  that  for  practical  purposes  the  steam-whistles,  as  at 
present  tried,  are  not  proved  to  be  advantageous  as  fog- 
signals. 

"  With  respect  to  the  usefulness  of  guns,  it  appears  from 
the  report  that 'they  possess  certain  disadvantages,  viz, 
the  short  duration  of  the  sound,  the  liability  of  that  sound 
to  be  quenched  by  local  noises,  and  its  comparative  ina- 
bility to  cope  with  an  opposing  wind.  Dr.  Tyndall  never- 
theless ranks  the  gun  as  a  first-class  signal,  an  opinion 
which  long  experience  of  its  use  confirms.  The  gun,  as  a 
signal,  is  well  known  to  mariners,  while  the  flash  is  also 
said  to  be  of  service  in  thick  weather.  With  regard  to  the 
guns  used  in  the  experiments,  it  appears  that  the  short  5J- 
iuch  howitzer,  with  a  3-pound  charge,  is  superior  to  the 
long  18-pounder  or  the  13-inch  mortar  with  the  same  charge, 
the  howitzer  having  generally  yielded  a  louder  and  more 
effective  report.  The  subject  of  a  special  gun  for  fog-signal 
purposes  is  now  under  consideration,  and  it  seems  probable 
that  both  in  effective  power  and  facility  of  working,  the 
gun  may  be  rendered  considerably  more  serviceable  than 
hitherto. 

"From  the  foregoing  observations  it  will  be  seen  that  at 
present  there  are  three  kinds  of  instrument  practically  avail- 
able fc>r  future  service  as  fog-signals,  viz,  the  siren,  the  trum- 
pet, and  the  gun,  and  as  further  experience  is  gained  with 
regard  to  these  instruments,  it  may  reasonably  be  expected 
that  great  improvement  will  be  made  in  them  and  that  the 
future  results  to  be  obtained  from  them  will  surpass  those 
now  recorded. 

"  It  will  be  well  now  to  consider  briefly  one  or  two  points 
in  connection  with  the  selection  of  a  site  for,  and  the  instru- 
ment to  be  used  as  a  fog-signal,  when  the  locality  has  been 
determined  upon.  In  the  investigations  the  question  as  to 
the  height  above  the  sea  at  which  it  is  desirable  that  a  sig- 
nal should  be  placed  has  received  some  attention,  and  the 
results  show  that  it  is  advantageous  that  such  signals  should 
be  placed  at  a  considerable  height  above  the  sea-level  in  or- 
der to  avoid  the  interference  caused  by  the  noise  of  waves 
breaking  on  the  shore,  the  rattle  of  pebbles,  &c.  The  com- 
parative trial  made  between  a  pair  of  horns  on  the  summit 
of  the  South  Foreland  cliff  and  another  pair  200  feet  below, 
close  to  the  sea- surf  ace,  proved  with  scarcely  an  exception 
that  the  higher  horns  were  superior  to  the  lower  ones.  From 
this  it  would  appear  advisable,  where  possible,  to  place  the 
signal  high  above  the  sea,  but  there  are  positions  on  our 


64  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

coasts  where  fog-signals  are  necessary,  and  yet  where  no 
considerable  elevation  could  be  obtained,  notably  Duuge- 
ness,  Orfordness,  &c.  For  such  positions,  therefore,  a  large 
and  powerful  siren  would  be  very  suitable  as  being  able  to 
overcome  the  noises  of  the  sea-shore.  For  river-banks,  light- 
vessels,  and  other  places  undisturbed  by  interfering  noises, 
a  smaller  instrument  of  the  same  description,  or  a  trumpet, 
would  prove  serviceable,  and  the  gun  would  be  a  fit  signal 
for  such  places  as  are  of  some  elevation  clear  above  the  sea, 
without  adjacent  outlying  rocks,  and  which  vessels  may  ap- 
proach i  close  to.7  It  is  not  intended  in  the  above  sugges- 
tions to  lay  down  any  system  which  shall  be  invariably  fol- 
lowed in  the  allocation  of  fog  signals,  but,  having  regard  to 
the  performances  of  the  instruments  referred  to  as  shown  in 
the  report,  the  foregoing  observations  may  be  regarded  as 
indicating  to  some  extent  how  the  respective  merits  of  the 
instruments  may  be  most  usefully  applied. 

u  While  upon  the  subject  of  fog-signal  sites  allusion  may 
be  made  to  the  caution  conveyed  in  the  report  that  in  select- 
ing the  position  for  a  fog-signal  the  possible  influence  of 
sound-shadow  must  be  taken  into  account.  This  is  a  point 
to  which  reference  was  made  in  the  report  of  your  committee 
to  America,  it  being  therein  recorded  that  in  the  experi- 
ments carried  out  at  Portland  Bay,  United  States,*  the  effect 
of  a  sound-shadow  was  distinctly  experienced,  and  four 
committee  stated  in  their  report  that  i  in  selecting  the  site 
fora  fog-signal  care  must  be  taken  that  no  outlying  point 
or  cliff  shall  interfere  with  the  arc  of  sound.'  It  is  satisfac- 
tory to  find  the  conclusion  of  that  committee  on  this  point 
entirely  borne  out  by  the  investigations  of  another. 

"  Another  important  conclusion  to  be  drawn  from  this 
report  in  regard  to  the  question  of  sites  is  that  no  signal 
should  be  required  to  mark  dangers  extending  seaward  more 
than  a  mile  or  a  mile  and  a  quarter.  The  minimum  effect- 
ive range  of  a  signal  being  2^  miles,  vessels  approaching 
such  dangers  and  coming  into  the  sound-range  would  have 
room  to  maneuver  and  be  able  to  keep  at  a  safe  distance. 
This  is,  of  course,  taking  the  minimum  range  of  the  signals, 
as  stated  in  the  report,  but  it  is  more  than  probable,  as  has 
been  stated  previously,  that  in  foggy  weather,  the  sound- 
range  being  extended  farther  than  the  minimum  limit  re- 
ferred to,  a  larger  range  may  be  allowed. 

"  Another  important  consideration  has  to  be  borne  in  mind, 
viz,  the  direction  in  which  sound  should  be  projected.  As 

*The  experiments  referred  to  have  been  carried  on  from  time  to  time 
for  some  years,  under  tlie  direction  of  Professor  Henrj. — E. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  65 

the  sound  of  a  signal  is  ascertained  to  be  most  effective  in. 
the  line  of  its  axis,  it  follows  that  the  instrument  should  be 
capable  of  such  adjustment  that  its  strongest  sound  may  be 
projected  directly  against  the  opposing  wind. 

u  It  is  to  be  observed  that  on  another  point  these  experi- 
ments confirm  the  opinions  expressed  by  your  committee  to 
America,  for,  with  regard  to  the  question  of  distinctions,  it 
is  clearly  shown  that  it  is  not  possible  to  rely  upon  dis- 
tiuctiveuess  of  note  alone,  for  the  mariner  would  not  appre- 
ciate such  a  distinction ;  indeed  the  siren,  horns,  and 
whistles  have  invariably  been  spoken  of  by  sailors  in  the 
vicinity  as  "  the  fog-horns."  Between  the  report  of  the  gun 
and  the  sound  of  the  siren  or  the  trumpet  there  is  a  perfectly 
intelligible  difference ;  but  for  further  purposes  of  distinction 
for  the  latter  instruments,  variation  of  the  length  of  the 
silent  interval  between  each  blast  offers  the  most  satisfac- 
tory means.  With  regard  to  this  point  it  will  be  seen  that 
Dr.  Tyndall  has,  with  some  reservation,  expressed  an  opin- 
ion which  hardly  seems  to  harmonize  with  the  experience 
of  the  Elder  Brethren.  Dr.  Tyndall  would  restrict  the 
silent  interval  to  a  length  of  30  seconds,  and  in  support  of 
his  opinion  draws  an  analogy  between  the  action  of  the  eye 
and  the  ear,  which  does  not  commend  itself  to  actual  nauti- 
cal experience.  The  board  will  probably  not  be  disposed 
to  waive  a  clear  advantage  in  power  and  great  scope  for 
distiuctiveuess,  in  order  that  the  longest  interval  of  silence 
should  not  exceed  30  seconds,  especially  with  the  knowl- 
edge that  guns  fired  at  intervals  of  a  quarter  of  an  hour 
have  proved  of  great  service  to  the  mariner  hitherto. 

"A  general  review  of  the  entire  report  shows  that  a  con- 
siderable amount  of  knowledge  has  been  gained,  both  as  to 
the  influence  of  the  atmosphere  in  the  transmission  of  sound 
and  to  what  extent  the  appliances  we  possess  may  be  relied 
on  for  producing  such  sounds  as  will  be  of  practical  service 
to  the  mariner.  We  have  learned  something  of  our  igno- 
rance in  regard  to  sound-transmission.  We  now  know  that 
the  varying  conditions  of  the  atmosphere  render  no  judg- 
ment infallible,  and  that  conclusions  founded  on  the  ex- 
perience of  to-day,  are  not  trustworthy  for  estimating  the 
results  of  the  morrow.  We  know,  moreover,  that  after 
bringing  forward  all  the  aid  which  science  can  at  present 
give  to  guide  the  mariner  in  thick  weather,  there  is  still  a 
large  element  of  uncertainty  and  mystifying  influence  with 
which  he  has  to  combat,  and  which  renders  it  incumbent 
on  him  to  use  the  greatest  caution  and  prudence  in  thick 
S.  Ex.  54 5 


66  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

weather,  to  regard  and  make  use  of  the  sound-signals  as 
means  for  assuring  the  vessel's  position,  and  not  as  aids  for 
running  at  high  speed ;  and,  above  all,  never  to  trust  so 
implicitly  to  sound-signals  as  to  neglect  the  use  of  the  sea- 
man's best  friend  and  truest  guide,  the  lead. 

"  The  subject  of  fog-signals  has  by  means  of  this  investi- 
gation received  a  great  impetus.  It  may  fairly  be  said  that 
we  have  taken  a  considerable  step  in  advance,  and  it  only 
remains  to  follow  it  up.  As  we  go  forward  our  experience 
will  widen,  and  although  it  is  more  than  probable  that  a 
few  years  of  practical  experience  and  testing  of  fog-signals 
will  materially  modify  our  present  views,  and  improve  con- 
siderably the  instruments  we  have,  yet  we  now  know  Jwiv 
to  go  forward  and  in  what  direction  to  head  our  efforts.  It 
is  to  be  hoped  that  before  very  long  our  coasts  will  be 
guarded  by  a  complete  chain  of  sound-signals,  all  effective 
and  useful  to  the  mariner.  No  unnecessary  delay  need  now 
occur  before  proceeding  to  supply  the  light-ships  and  the 
important  stations  already  selected  by  the  board,  and  when 
they  are  all  established  the  lights  rendered  useless  at  a 
quarter  of  a  mile  by  fog  will  be  superseded  by  sound-signals 
capable  of  warning  the  mariner  at  a  distance  of  three  miles. 

"  It  is  almost  unnecessary  to  add  that  in  thus  giving 
practical  effect  to  the  spirit  of  the  recommendations  of  this 
valuable  report,  the  Elder  Brethren  will  have  the  satisfac- 
tion of  knowing  they  are  acting  in  the  highest  interests  of 
humanity  and  conferring  an  inestimable  boon  on  the  nauti- 
cal community  at  large." 

SOUTH  FORELAND. 

Location  Tlie  great  electric  lights  at  South  Foreland,  two  in  num- 

ber, are  three  miles  east  of  Dover  Pier,  on  the  high  chalk-cliffs 
overlooking  the  Strait  of  Dover,  from  which  can  be  seen  Gris- 

Height  of  focal nez  an<*  otaer  French  lights.    They  are  about  1,000  feet  apart, 

planes!  the  high  light  372,  the  low  one  275  feet  above  the  sea,  and  form 

a  range  or  lead  as  a  guide  to  clear  the  Goodwin  Sands,  one 

of  the  greatest  dangers  in  British  waters.    A  general  plan 

of  the  establishment  is  shown  in  Plate  I. 

Engine-house.  A  fire-proof  engine-house,  a  plan  of  which  is  shown  in 
Plate  II,  is  placed  midway  between  the  towers,  and  con- 
tains the  magneto-electric  machines,  the  engine-room,  boiler- 
room,  coal-room,  and  two  repair-shops.  Near  by  are  the 
dwellings  of  the  engineer  who  superintends  the  establish- 
%  ment,  and  those  of  some  of  the  keepers,  there  being  six  at 

this  station. 


X 
nO 

il 

«o 

ic 
P| 

O 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  67 

The  electric  current  is  generated  by  means  of  large  mag-    Magneto-eiec- 

,    trie  machines. 

neto-electric  machines,  two  of  which  are  provided  for  each 
light,  though  habitually  in  clear  weather  but  one  machine 
is  used  for  each.    These  machines  are  driven  by  means 
belting  connected  with  a  steam-engine,  a  duplicate  of  which 
is  kepi  for  use  in  case  of  accident  or  repairs.    The  boilers, 
which  are  of  the  ordinary  locomotive  class,  are  also  in  du- 
plicate.    About  56  pounds  of  coke  per  hour  are  consumed    coke  used. 
during  the  night  5   during  the  day  the  fijes  are  banked. 
One  of  these  electric  machines  is  of  French  manufacture.    Machines     of 
having  been  made  by  the  Compagnie  V Alliance  of  Paris.    The  giisn    manafac- 
others  are  English-made  machines  of  Professor  Holines'stl~ 
patent,  and  are  considered  by  the  Elder  Brethren  to  be  su- 
perior, though  the  French  appeared  to  be  the  simpler  in  con- 
struction and  is  the  one  shown  to  visitors  in  explaining  the 
operation  of  generating  the  electric  current.     This  operation 
is  fully  illustrated  in  the  description,  which  will  be  found  .Description 

givenatLaHeve. 

further  on,  of  the  magneto-electric  lights  at  La  Heve  near 
the  mouth  of  the  Seine. 

It  may  be  well  to  state  here,  however,  that  each  machine    Helices, 
is  composed  of  ninety- six  helices  mounted  upon  six  gun- 
metal  wheels,  each  having  sixteen  helices. 

Between  these  wheels  are  placed  the  magnets,  eight  in  Magnets. 
each  division,  forty  of  which  are  composed  of  six  layers  or 
leaves  riveted  together,  and  sixteen  (the  end  ones)  similarly 
constructed  but  having  only  three  leaves  or  layers.  These 
magnets,  which  are  mounted  in  frames,  are  stationary,  while 
the  helices  revolve  at  the  rate  of  four  hundred  revolutions 
per  minute. 

The  power  absorbed  by  the  machine  alone,  disregarding   Power  required 

«.,..,.          .     ,.  &  for  operating  the 

friction,  is  four  indicated  horse-power,  and  the  actual  power  machines. 
required  to  work  one  of  the  machines,  including  the  friction 
of  engine  and  shafting,  is  six  indicated  horse-power. 
The  power  of  a  magneto-electric  machine  is  according  to 

Power  of   the 

the  gross  attractive  power  of  its  magnets,  each  magnet  hav-  machines, 
ing  a  certain  lifting  or  attractive  power,  (expressed  in 
pounds.)  In  the  machines  at  South  Foreland  each  of  the  six- 
plate  magnets  will  lift  108  pounds,  and  each  three-plate 
magnet  will  lift  54  pounds,  making  the  attractive  power  of 
the  magnets  in  one  machine  to  be  40x108+16x54=5,184 
pounds.  This  may  be  considered  as  expressing  the  power  of 
the  machine.  The  proportion  of  the  lifting  power  to  the 
actual  weight  of  a  magnet  is  a  good  indication  of  its  value, 
and,  generally  speaking,  a  magnet  which  will  lift  two  and 
one-half  times  its  own  weight  is  a  good  one.  Each  six-plate  ne^flue  of  mag" 
magnet  at  South  Foreland  has  a  weight  of  43J  pounds,  and 


68  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

will  lift  108  pounds.  The  total  weight  of  all  the  magnets 
in  one  machine  is  2,088  pounds,  the  total  attractive  power 
being,  as  stated,  about  5,184  pounds. 


in°  madSe?  Sid     ^ne  macnines  are  connected  with  the  electric  lamps  placed 
lamps.  in  the  lenses  of  the  tower  by  underground  cables. 

fe2o?nk  Vyndaii     The  maimer  of  operating  these  machines,  the  arrangements 
for  explanations,  of  ^ne  lenses,  lamps,  &c.,  were  carefully  explained  to  me  by 
Professor  Tyndall,  who  had  kindly  accompanied  me  through 
the  station,  and  who  spared  no  efforts  to  make  my  inspec- 
tion a  thorough  and  minute  one. 

Carbon  points.  Each  lamp  contains  two  pieces  of  carbon,  each  of  which 
is  about  10  inches  long  by  three-eighths  of  an  inch  square. 
These  are  placed  end  to  end,  one  above  the  other,  and  are 
kept  at  the  proper  distance  apart  by  an  automatic  apparatus. 
The  current  leaps  across  the  small  space  separating  the 
1  carbons/  and  a  series  of  sparks  is  formed,  but  so  rapidly 
that  the  eye  cannot  separate  them,  and  a  most  brilliant 
light  is  produced.  By  the  automatic  apparatus  the  carbon 
pencils  are  moved  toward  each  other  as  fast  as  they  are 
consumed,  and  the  only  danger  of  irregularity  of  the  lights, 
Danger  from  jf  the  machines  and  cables  are  in  good  order,  arises  from 

ill©     pr6S6DC6     Ot  ' 

inrtnfIcarb1onster  ^e  Presence  °f  foreign  matter  in  the  carbons.  I  was  told 
by  the  keepers  that  the  carbons  in  use  give  them  trouble 
in  this  particular,  the  lights  being  sometimes  extinguished. 
This  is  only  for  an  instant,  however,  as  all  that  is  neces- 
sary to  relight  them  is  to  bring  the  carbons  in  contact, 
after  which  they  are  replaced  in  their  proper  positions. 

foi^nlnagfngthe  Tne  arrangements  for  bringing  the  electric  light  to  the  focus 

light.  of  ^he  iengj  an(j  for  feeding  the  carbons  as  fast  as  they  are 

consumed,  are  simple  and  ingenious,  and  the  duties  of  the 
keepers,  beyond  watching  for  the  occurrence  of  imperfec- 
tions in  the  carbons,  are  very  light.  tThese  carbons  are 
made  from  coke-dust;  their  rate  of  consumption  is  34  inches 
per  night  for  each  light,  at  a  cost  of  one  penny  per  -inch, 
exclusive  of  waste  and  breakage. 

Lenses.  The  lenses  in  use  at  South  Foreland  are  of  about  the 

same  size  as  ordinary  third-order  lenses,  (39  inches  interior 
diameter,)  and  were  especially  designed  for  the  electric 
light  and  this  locality  by  Chance  Brothers  &  Co.,  of  Bir- 
mingham. 

iu5Stionarc°f  Tne  arc  of  illumination  required  being  but  little  more 
utilizing  the  than  180°,  the  rear  light  is  ingeniously  utilized  to  re-en- 
force the  other  by  means  of  totally  reflecting  prisms,  and  it 
was  observed  that  a  much  greater  development  was  given 
to  the  catadioptric  prisms  below  the  central  belt  than  can 
be  done  in  the  use  of  the  large  burners  of  the  oil-light. 


^       S      .*       ^     ^      .>.      Q 


a 

3D 
O 

0 

•o 


5C 


o 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  69 

Both  lights-  are  fixed,  and  illumine  somewhat  more  than  Description  of 
half  the  horizon.  In  both  the  portion  of  light  which  would  tus!°a 
otherwise  be  wasted  landward  is  led  round  by  subsidiary 
apparatus  to  intensify  the  illuminated  arc ;  but  the  low 
light  presented  the  peculiarity  that  it  was  desired  to  light 
the  sea  brightly  from  the  horizon  to  300  yards  from  the  base 
of  the  tower,  and  as  the  height  of  the  focal  plane  is  290 
feet  above  the  sea,  this  requires  that  a  portion  of  the  light 
should  dip  below  the  horizontal  plane  no  less  than  17°  23'  32", 
while  the  major  portion  should  go  to  the  sea-horizon.  This 
requirement  was  met  in  the  following  manner:  The  light  Main  appara- 
frorn  both  the  top  and  bottom  systems  of  reflecting  prisms  u 
was  directed  wholly  to  the  horizon,  while  the  central 
refracting  portion  of  the  cupola  was  specially  arranged  to 
give  tlie  required  dip.  The  latter  consists  of  sixteen  re- 
fracting segments,  eight  above  and  eight  below  the  focal 
plane,  there  being  no  central  refracting  belt  as  is  usually 
the  case.  These  refracting  segments  are  so  arranged  that 
the  intensity  of  the  light  viewed  from  the  point  distant 
300  yards,  or  from  the  horizon,  is  sensibly  the  same ;  also, 
that  no  portion  of  the  sea  shall  depend  for  its  illumination 
on  one  prism  only,  as  otherwise  that  point  might  be  placed 
in  total  darkness,  owing  to  a  lantern-bar  or  other  obstacle 
intercepting  the  light. 

The  arrangement  adopted  for  using  the  light  which  would  subsidiary  ap- 
otherwise  be  wasted  toward  the  land  is  symmetrical  about  Paratus- 
the  middle  line  of  the  apparatus,  each  half  consisting  of  a 
portion  of  a  holophote,  and  of  a  frame  of  six  vertical  prisms. 
The  former  condenses  the  light  of  the  spark  into  a  beam. of 
horizontal  parallel  rays,  which  pass  to  the  side  of  the  appa- 
ratus and  are  there  distributed  over  half  the  illuminated 
arc  by  the  vertical  prisms.  The  rays  emerging  from  these 
prisms  do  not  pass  through  a  single  focus  as  in  lights  pre- 
viously constructed  on  the  azimuthal  condensing  plan,  but 
each  prism  has  a  special  focus  so  situated  that  the  light  is 
equally  distributed  over  the  arc  illuminated.  Probably  the 
plan  of  a  common  focus  was  adopted  in  some  earlier  cases 
as  simpler  for  calculation,  and  also  in  order  to  facilitate  the 
examination  of  the  apparatus  for  adjustment,  but  the  exam- 
ination can  be  conducted  with  equal  accuracy  with  special 
foci,  and  no  trouble  should  be  spared  to  render  such  an  ap- 
paratus as  perfect  as  possible.  The  outer  prism  of  the  set 
is  of  a  special  and  difficult  construction,  required  because 
the  arc  it  has  to  illumine  is  situated  at  so  great  an  angle 
from  the  direction  of  the  rays  it  receives.  Prisms  of  a  sim- 
ilar construction  had  been  previously  suggested  by  Mr. 


70  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Thomas  Stevenson,  engineer  of  the  Scottish  lights,  and  have 
been  used  by  Mr.  James  Chance  in.  several  other  instances. 
In  cases  like  the  South  Foreland,  many  plans  for  attaining 
the  end  in  view  suggested  themselves.  It  might  be  pro- 
posed that  some  arrangement  similar  to  the  subsidiary  one 
at  Souter  Point  (which  will  be  described  further  on)  should 
be  used.  Such  an  arrangement  would  be  unsuitable  in  the 
case  of  South  Foreland,  for  various  reasons,  among  which 
may  be  mentioned  that  the  light  would  pass  through  three 
optical  agents  instead  of  two.  At  Souter  Point,  the  light 
being  revolving,  the  only  feasible  plan  was  to  take  the  spare 
light  downward  through  the  pedestal.  Again,  the  central 
cupola  might  have  been  continued  entirely  round  the  spark 
and  the  spare  light  from  the  land-side  of  the  cupola  reflected 
seaward  by  large  vertical  prisms.  This  plan  was  rejected 
on  account  of  its  being  unnecessarily  expensive,  and  for 
other  reasons.  The  advantages  of  these  and  other  plans 
were  considered  by  Mr.  Chance  before  he  adopted  the  ar- 
rangement shown  on  the  drawing. 

Moderator-     To  supply  any  contingency  necessitating  its  use  a  u  mod- 
lamp  for  use  in  _,          __         ,         ,  _ 

case  of  accident,  erator"  oil-lamp  is  placed  under  the  electric  lamp  and  can 
be  quickly  substituted  for  it.  This  lens  is  shown  in  eleva- 
tion and  plan  in  Plate  III,  in  which  a  and  a'  show  the  elec- 
tric lamp  in  position  and  withdrawn  for  removing  the  car- 
bon pencils ;  b  ft,  the  carbon  pencils  ,•  c  c,  the  electric  wires  ; 
d,  the  bed-plate ;  e^  the  burner  of  the  oil-lamp ;  /,  the  tele- 
scopic supply  and  overflow  pipes  for  the  oil  ;  #,  the  oil-lamp  ; 
7t,  elevation  of  one  of  the  half-holophotes ;  li'  h',  the  two  half- 
holophotes  in  plan ;  i  i,  %'  i',  vertical  condensing  prisms. 
In  substituting  the  oil  for  the  electric  light,  the  bed-plate 
d  is  removed  and  the  oil-burner  e  is  run  up  to  the  focus  by 

Power  of  eiec-  means  of  a  rack  and  pinion.  The  power  of  the  uii condensed 
beam  from  each  of  the  electric  lights  at  South  Foreland,  i.  e. 
of  the  naked  light  without  the  condensation  of  the  rays 
produced  by  the  lenses,  is  equal  to  the  combined  light  of 
2,000  candles,  Avhile  the  corresponding  power  of  the  four- 
wick  sea-coast  light-house  oil-light  is  328  candles.  Estimat- 
ing the  power  of  the  condensed  beam  from  the  South  Fore- 
land lenses  as  ninety  times  the  power  of  the  naked  light, 
(which  is  the  result  of  Mr.  Chance's  calculation  of  the  con- 
densing-power  of  the  South  Foreland  lenses,)  we  have  for 
the  power  of  the  beams  from  each  of  the  electric  lights  at 
South  Foreland,  180,000  candles  ! 

observations  at     I  was  shown  the  method  of  lighting  the  electric  lamp, 

night  ft          er  ^^  .^  ^e  evening  observed  the  two  lights  from  Dover  Pier. 

While  the  upper  light  was  decidedly  the  superior,  the  lower 


SOUTH  FORELAND  LIGHTHOUSES. 

ELECTRIC  LIGHTS. 


PLATE  ill 


DETAILS 

or 
LANTERN  AND   LENS 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  71 

waxing  and  waning  very  perceptibly,  which  was  caused,  as 
Mr.  Douglass  informed  me,  by  some  imperfection  in  the  ma-' 
chiuery,  both  of  them  surpassed  anything  I  had  ever  seen, 
and  I  could  not  convince  myself  that  they  were  three  miles 
off.  Even  at  this  distance,  the  shadows  of  objects  on  the 
pier  were  very  distinct. 

The  towers  supporting  these  lights  are  not  high,  (their 
site  being  an  elevated  one,)  and  they  are  attached  to  keep- 
ers' dwellings.     The  buildings  are  all  constructed  in  the    Buildings, 
most  substantial  manner,  and  each  dwelling  is  sufficient  for 
the  accommodation  of  two  keepers  and  their  families,  with 
room  for  the  supernumeraries  who  are  kept  at  the  station 
for  instruction.    The  steam-engineer  (the  principal  official  of   Machines  man 
the  establishment)  and  the  principal  light-keepers  are  com-  SSgmeer  8  Tnli 
petent  to  manage  the  engine  and  magneto-electric  machines,  11™C1] 
and  they  attend  to  this  duty  in  turn.    No  laborers  or  fire- 
men are  employed.    The  dwellings  at  this  station,  as  at  all 
the  stations  I  visited  on  the  English  coast,  were  kept  ex- 
tremely neat.     Rooms  for  accommodation  of  any  visiting  coj™™dsation  aoi 
officer  of  the  Trinity  House  are  fitted  up  in  the  dwelling  ^J^J     House 
attached  to  the  engine-house,  and  everything  is  provided 
for  his  comfort,  even  to  a  full  set  of  table-furniture. 

Attached  to  the  central  station  (the  engine-house)  are  the  store-rooms. 
different  store-rooms  for  the  supplies,  which  inplude  lubri- 
cating and  colza  oils,  the  latter  for  use  in  the  lenses  in  case 
of  failure  of  the  electric  light  or  of  other  accident ;  but  I 
believe  it  Ips  rarely  if  ever  been  needed.  Some  of  the  oil- 
butts  are  of  tin,  the  others  of  galvanized  sheet-iron.  ou-butts. 

The  colza  (rapeseed)  oil  is  of  a  pale  sherry-color,  very    coiza-oii. 
clear  and  limpid,  with  a  strong  and  peculiar  vegetable  odor. 

In  all  the  houses  the  steps  and  stairs,  as  well  as  the 
paving  of  all  the  halls  and  corridors,  were  of  stone,  rubbed 
once  a  week  with  Bath-stone,  which  produces  a  color  like 
that  given  by  a  wash  of  hydraulic  cement. 

In  the  towers,  and  also  at  the  engine-house,  speaking- 
tubes  are  arranged  to  communicate  from .  one  to  the  other,    Speaking- 
and  for  the  purpose  of  calling  relief.    I  found  such  tubes  at 
all  the  stations  I  visited.    Each  keeper's  watch  is  four  hours. 

Both  watch-rooms  and  lanterns  at  South  Foreland  are    watch-rooms 
considerably  larger  and  more  commodious  than  our  own.      Serf  lanterns' 

At  each  dwelling  is  an  earth-closet,  placed  in  an  out- 
building,  in  which,  instead  of  earth,  the  ashes  produced  at 
the  station  are  used,  and  I  was  informed  that  the  use  of 
earth-closets  at  light-stations  is  universal,  and  gives  entire 
satisfaction. 


72  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Fire,  means  for  Means  for  extinguishing  accidental  fires  are  provided  by 
extinguishing.  ^ie  engjne  which  drives  the  magneto-electric  machines. 
The  pumps  are  connected  by  pipes  to  each  of  the  towers  and 
dwellings,  the  water  being  drawn  through  the  chalk,  from 
a  well  at  a  depth  of  200  feet,  during  high  tide  in  the  Strait 
of  Dover,  when  the  water  backs  up  into  the  well.  Reser- 
voirs are  provided  for  use  at  low  water. 

Meteorological     Two  keepers  are  designated  for  each  tower,  who,  in  addi- 
tion to  their  other  duties,  make  daily  observations  with  the 
barometer  and  with  wet  and  dry  bulb  thermometers,  keep- 
ing memoranda  for  the  use  of  some  department  of  the  gov- 
The  keepers,    ernmeut.    The  two  principals,  who  are  assistants  to  the  en- 
gineer, I  found  to  be  very  intelligent  men  who  seemed 
thoroughly  to  understand  the  magneto-electric  machines, 
and  who  gave  me  a  very  accurate  account  of  their  opera- 
tion.   One  of  them  was  by  trade  a  watch-maker,  and  the 
other  a  stone-mason.     The  latter  told  me,  with  evident 
pride,  that  he  had  laid  all  the  stone  at  the  Bishop  Rock, 
near  the  Scilly  Islands,  one  of  the  most  exposed  stations  in 
the  English  service,  and  had  been  for  some  years  the  prin- 
cipal keeper  of  that  light,  a  position  he  was  obliged  to  re- 
sign, the  close  confinement  affecting  his  health.    Each  ot 
these  men  had  been  more  than  fifteen  years  in  the  service. 
Cost  of  mainte-     The  annual  cost  of  maintenance  of  a  si'ngle  electric  English 
nance  of  light.    light  is  about  £800)  (or  $4,000,)  about  double  that  of  a  first- 
order  single  oil-light  station,  while  the  light  produced  by 
the  former  is  between  six  and  seven  times  tbat$)f  the  most 
powerful  lens  with  the  four-wick  Douglass  oil-burner. 
cost  of  substi-     The  approximate  cost  of  substituting  at  a  double-light 
iightgappar£^  station,the  magneto-electric  lights  as  used  at  South  Foreland 
&c.,foi  £or  ^je  oil-lights  commonly  used  is  as  follows : 

Building  works £7, 360  $36,  800 

Lantern  and  dioptric  apparatus 3,  088  15,  440 

Electric-apparatus 5, 356  26,  780 

Miscellaneous 650  3,250 

Total ....£16,454        $82,270 

I  am  indebted  for  my  detailed  description  of  the  excel- 
lent optical  apparatus  at  South  Foreland  to  the  manufac- 
turers, Messrs.  Chance,  Brothers  &  Co.,  of  Birmingham. 

THE  ROMAN  PHAROS  IN  DOVER  CASTLE. 

visit  to  Dover     Through  the  kindness  of  Colonel  Collinson,  of  the  Royal 

Castle.  Engineers,  I  had  an  opportunity  of  visiting  the  castle  at 

Dover,  and  of  attending  a  review  of  the  three  regiments  of 

Kent  County  militia,  and  of  the   garrison  of  three  regi- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  73 

inents  of  regular  troops.  Colonel  Collinson  showed  ine 
many  objects  of  great  interest — the  grand  old  castle,  from 
which  were  distinctly  visible  the  coasts  of  France,  the  tow- 
ers of  the  cathedral  of  Boulogne,  and  the  light-house  at  Calais, 
on  the  other  side  of  the  Channel ;  the  rooms  occupied  by 
Charles  I  and  by  Queen  Elizabeth  ;  the  church  of  Saint  Mary, 
Within  the  Castle,  founded  A.  D.  161,*  and  the  modern  exte- 
rior forts  ;  but  nothing  was  more  interesting  to  me,  consid- 
ering the  nature  of  my  mission  to  Europe,  than  the  old 
pharos  within  the  castle  walls,  the  present  condition  of 
which  is  represented  in  Eig.  1. 

Fig.  1. 


Roman  pharos  in  Dover  Castle. 

The  antiquity  of  this  light-house,  which  has  not  proba- 
bly been  used  as  such  since  the  Conquest,  no  doubt  ex- 
ceeds that  of  any  light-house  in  Great  Britain,  and  it  is 
supposed  to  have  been  built  in  the  reign  of  the  Emperor 
Claudius,  about  A.  D.  44.* 

Upon  it  burned  for  many  centuries  those  great  fires  of 
wood  and  coal  formerly  maintained  on  several  towers  still 
standing  on  the  coasts  of  Great  Britain.  These  earliest 
guides  to  mariners  at  length  gave  way  to  reflectors  5  they, 
in  their  turn,  being  replaced  in  the  year  1819  by  that  great  Date  of  inven- 
triumph  of  scientific  skill,  the  Eresnel  lens.  8y8ntemheFre8nel 

The  pharos,  like  its  sister  light-house,  the  Tour  d'Ordre   construction  of 
at  Boulogne,  is  built  of  brick,  in  color  and  shape  like  those tbe  pharos- 
in  the  Eoman  structures  found  elsewhere  in  Great  Britain  ;    Description  of 
they  are  of  a  light-red  color,  about  14  inches  long,  and  not theEomanbrick8- 
more  than  an  inch  and  a  half  thick.    This  latter  dimension 

*  Hasted's  History  of  Kent. 


74  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

is  but  little  more  than  the  thickness  of  the  joints,  which  are 
filled  with  a  mortar  composed  of  lime  and  finely-powdered 
Eoman  brick.  The  preservation  of  this  famous  relic  of  the 
.Romans  in  England  is  doubtless  due  to  the  fact  that  some 
centuries  ago  the  tower  was  turned  into  a  belfry  for  the 
church  of  Saint  Mary,  and  was  surrounded  by  walls  of  stone. 
These  are  now  nearly  destroyed  by  time,  and  the  old  Roman 
work  is  again  exposed. 

While  the  Trinity  House  steam-yacht  Vestal,  in  which  I 
was  to  take  my  first  cruise  among  the  English  lights,  was 
fitting  out  for  her  annual  voyage  to  the  northeast  coast 
of  England,  I  made  frequent  visits  to  the  Trinity  House, 

visits  to  Trin-  where  I  was  always  cordially  welcomed,  and  thus  I  acquired 
much  information  regarding  the  English  light-house  sys- 
tem. 

Kindness  re-     I  received   much  kindness  in  many  ways  from  Sir  Fred- 

cewecl   from  Sir 

Frederick  Ar-  erick  Arrow,  and  on  the  21st  of  May  accompanied  him  to  a 
dinner  at  the  Mansion  House,  to  which,  through  his  good 
Dinner  at  the  offices,  I  had  the  honor  to  be  invited  by  the  Lord  Mayor  and 
Lady  Mayoress,  by  whom  it  was  given  in  honor  of  the  re- 
turn of  the  Master  of  Trinity  House,  the  Duke  of  Edin- 
burgh. About  three  hundred  guests  were  present,  and  it 
was  a  highly  enjoyable  and  interesting  occasion. 

In  his  response  to  a  toast  to  the  Trinity  House,  His  High- 
spoke  of  the  gratitude  of  the  corporation  for  the  serv- 
-  ices  rendered  Sir  Frederick  Arrow  and  Captain  Webb  of  the 
Spta^n°webbElder  Brethren  during  their  stay  in  this  country,  (to  which 
Smites'16  Uni  ^  nave  Before  referred.)  and  commissioned  me  to  convey  his 
thanks  to  my  associates  of  the  Light-House  Board  of  the 
United  States.    While  the  services  referred  to  were  insignifi- 
cant as  compared  with  those  rendered  to  me  while  in  England, 
I  was  much  gratified  by  the  highly  complimentary  terms  in 
which  he  mentioned  our  country,  and  particularly  our  light- 
house establishment. 

interview  with     While  in  London  at  this  time  Captain  Doty,  patentee  of  a 

captain  Doty.     blirner    for  light-house  illumination,  addressed  me  a  note 

The  Doty  lamp,  requesting  an  interview,  which  request  I  complied  with,  and 

he  showed  me  his  lamp,  which  has  been  patented  in  several 

countries,  including  the  United  States.     It  combines  the 

outer  "  cone  "  or  "jacket,"  the  central  u  button  "  and  adjust- 

able gallery,  but  has  not  the  conical  "  tips"  peculiar  to  the 

tamSoty  that  fhe  Douglass  lamp,  which  also  comprises  the  above  improve- 


Captain  Doty  claims  that  the  Douglass  or  Trinity 
pategnetmeiltofhi8  House  lamp  is  an  infringement  of  his  patent,  and  the  ques- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  75 

tion  has  been  before  the  courts,  with  what  results  I  am  not 

fully  informed,  but,  as  I  found  in  my  subsequent  inspection, 

the  English  are  rapidly  changing  their  light-house  lamps  ne^n^  8us.JDg 

for  those  of  the  Douglass  pattern,  and  their  illuininant  from  mineral™!!? 

colza  to  mineral  oil. 

Both  the  Doty  and  the  Douglass  lamp  are  especially    Lamps  adapted 
designed  for  burning  the  latter,  though  they  are  equally10 
adapted  to  the  use  of  vegetable  and  animal  oils. 

Captain  Doty  claims,  among  other  things,  to  have  first  sug-  ^rtj^otaims 
gested  the  great  economy  in  the  use  of  mineral  oil,  and  that 
the  invention  of  his  lamp  made  its  use  practicable  in  light- 
house illumination.     He  stated  that  the  French  government 
had  issued  a  general  order  to  change  all  the  lights  on  the 
coast  of-  France  from  colza  to  mineral  oil ;  that  the  Scotch 
were  rapidly  introducing  such  oil  for  use  in  their  light- 
houses, and  that  his  lamp  had  been  adopted  by  France, 
Scotland,  and  Sweden.    Judging  from  my  observations  at   opinion  regard- 
the  trial,  (which,  however,  was  not  comparative,)  I  believe  j2np.the 
Captain  Doty's  lamp  to  be  an  excellent  one.    Of  his  claim 
to  priority  of  invention  I  was  not  sufficiently  informed  to 
judge  $  but,  from  what  I  afterward  learned  in  Paris  from 
M.  Lepaute,  who  showed  me  the  lamp  invented  by  his 
father  in  1845,  I  am  inclined  to  doubt  if  such  claim  can  be    Doubt  as  to 
sustained,  though  I  do  not  question  the  fact  that  Captain 
Doty  is  entitled  to  much  credit  for  having  directed  attention  ot  in™ntion. 
to  the  advantages  to  be  gained  by  the  adoption  of  mineral 
oil  for  light-houses. 

One  evening,  after  dining  with  Professor  Tyndall  at  his  observation  of 
club,  I  went  with  him  to  observe,  from  the  terrace  on  which 
stands  the  Duke  of  York's  column,  the  competitive  gas  and 
electric  lights  on  Westminster  clock-tower.  The  electric 
light  I  have  already  described  in  my  account  of  the  South 
Foreland  light-station  ;  the  gas-light  will  be  fully  de- 
scribed in  my  treatment  of  the  subject  of  Irish  light-houses. 

It  may  be  well,  however,  to  state  here  that  in  the  experi-  Wignara  burner. 
mental  gas-light  on  Westminster  clock-tower  three  Wigham 
burners  (each  composed  of  108  jets,  but  so  arranged  as  to 
burn  28,  48,  68,  88,  or  108  jets  as  desired)  were  placed  one 
above  another,  at  a  distance  of  three  feet  from  center  to 
center.   Before  the  lower  one  was  a  refracting  belt  of  a  first-  bu?ieprssitl°n  °f 
order  dioptric  apparatus  for  a  fixed  light ;  before  the  upper 
two  burners  were  placed  two  refracting  panels  of  a  first- 
order  apparatus  for  revolving  light,  each  panel  being  for  an 
arc  of  45°.    These  panels  were  arranged  for  rotating  before  lo 
the  flame  and  producing  in  combination  with  the 


7G  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Brilliancy  of  belt,  n  fixed  light  varied  by  flashes.  Both  of  these  lights 
were  magnificently  bright,  but  their  nearness  to  our  place 
of  observation  was  unfavorable  to  a  comparative  test,  and 

Elongated  ap-  caused  the  gas-light  to  appear  vertically  elongated,  an  effect 

gSSigEt.  oi    be  which  my  subsequent  observations  of  the  gas-light  in  actual 

use  in  light-houses  on  the  coast  of  Ireland  and  east  coast  of 

England  convinced  me  was  not  a  necessary  feature  of  the 

e?uiiarsht  ^"if  svstem-  ^ne  reddish  tinge  which  prevailed  in  the  gas  much 
more  than  in  the  electric  light  would  probably  enable  it  to 
more  successfully  penetrate  fog. 

^r*  -^ou^ass  found  the  power  of  this  gas-light,  burning 
108  jets,  the  beam  being  uncondensed  by  lenticular  appa- 
ratus, to  be  equal  to  that  of  1,199  candles  when  consuming 
300  feet  of  cannel-coal  gas  per  hour  of  the  illuminating  value 
of  25  candles. 

TRINITY  HOUSE  DEPOT    AT  BLACKWALL. 

visit  to  depot.  On  the  llth  of  June  I  went  by  rail  to  visit  the  principal 
depot  of  the  Trinity  House  at  Black  wall,  on  the  Lower 
Thames.  This  depot  is  much  the  same  as  our  own  at  Staten 
Island,  New  York  Harbor,  but  at  the  former  are  repaired 

Light-ships  re- the  numerous  light-ships  employed  on  the  coast  above  and 
below  the  mouth  of  the  Thames,  while  our  light-ships  are 
repaired  at  private  yards, 

Grounds.  The  grounds  are  rather  limited  in  extent,  and  some  of  the 

buildings  are  old  and  inconvenient,  but  facilities  for  all 
kinds  of  work  and  for  storage  are  as  good  as  can  be  ob- 
tained until  the  additional  area  which  is  desired  can  be  pur- 
chased. 

Lamp-shop.  The  lamp-shop  is  very  complete  in  its  appointments,  and 
a  large  number  of  men  are  employed  there.  Many  of  them 
are  constantly  engaged  upon  the  manufacture  and  repair 
of  the  catoptric  apparatus  for  light-ships,  of  which  the 
English  have  a  great  number. 

Reflectors  stiii  Jn  many  of  the  light-houses  reflectors  are  still  in  use,  being 
considered  better  than  lenses  for  some  localities,  especially 
for  range  or  u  leading"  lights. 

Light-ship  ap-  The  apparatus  for  light-ships  is  hung,  as  in  our  own  service, 
upon  a  universal  joint,  and  an  ingenious  improvement  has 
been  recently  adopted,  by  which  the  reflector  is  adjusted  by 
passing  the  shaft  of  the  gimbal  through  slots  which  allow 
it  to  be  moved  backward  or  forward,  and  the  face  of  the 
reflector  maintained  in  a  vertical  position. 

Douglass  lamp.      In  the  new  Douglass  lamp,  which  is  being  rapidly  sup- 
plied to  all  English  light-houses,  the  light  may  be  increased 


s 


o 

c 

0) 

n 
OQ 

3D 

n 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


77 


1 


as  desired  in  thick  and  foggy  weather,  being  in  this  regard 
similar  in  effect  to  the  electric  and  gas  lights,  although  it  is 
not  possible  to  make  the  proportionate  increase  so  great 
with  oil-lrght  as  with  those  just  mentioned. 

These  lamps  are  of  different  orders.  Among  those  I  saw  Six-wick  lamp, 
at  Blackwall  was  the  six-wick  lamp  for  mineral  or  colza  oil, 
(in  which  mineral  oil  was  to  be  used,)  designed  to  be  placed 
in  one  of  the  towers  at  Haisborough,  on  the  east  coast  of 
England,  for  experimental  comparison  with  the  gas-light, 
which  will  receive  mention  when  I  come  to  describe  that 
station.  • 

This  lamp  is  called  by  Mr.  Douglass  the  "  lamp  of  single  Description. 
and  double  power,"  from  its  capacity  for  increasing  or 
diminishing  the  light  to  suit  the  state  of  the  atmosphere. 
For  example,  in  the  case  of  the  six- wick  burner,  shown  in 
Plate  IV,  the  ordinary  fair-weather  light  is  produced  by  the 
flame  from  the  outer  three  wicks  only,  but,  as  the  weather 
becomes  thick  or  foggy,  the  inner  three  may  be  successively 
lighted,  increasing  the  power  of  the  flame  from  342  to  722 
candles — more  than  double  its  fair-weather  power. 

These  lamps  burn  either  animal,  vegetable,  or  mineral 
oil.  The  burner  of  one  for  six  wicks  is  shown  in  Plate  IV, 
in  which  figures  A  and  B  are  elevations  showing  the  ad- 
justment for  burning  mineral  and  colza  oils  respectively, 
and  figure  0  is  a  section  of  the  latter  ;  a  is  the  chimney- 
holder  ;  1)  b  the  chimney ;  c  the  exterior  deflector ;  d  the 
outer  wick-case ;  e  the  inner  cases ;  /the  central  air-space  ; 
(/the  interior  deflector  ;  A'  and  A"  plan  and  section  of  in- 
terior deflector  for  mineral-oil ;  B'and  B"the  same  for  colza- 
oil  ;  D  the  central  button,  and  E  an  enlarged  view  of  the 
burner-tips. 

In  burning  mineral  oil  the  wicks  are  raised  about  one-    Use  of  mineral 
sixteenth  of  an  inch  above  the  tips  of  the  burners,  and  the 
exterior  deflector  is  kept  in  the  position  shown  at  A  in 
Plate  IV. 

In  burning  colza  the  wicks  are  raised  about  five-six- 
teenths of  an  inch  above  the  tips  of  the  burners.  The  oil 
overflows  as  in  our  lamps,  and  the  exterior  deflector  is 
placed  as  shown  at  B,  Plate  IV. 

About  one  and  one-fourth  inches  below  the  tops  of  the  wick- 
cases  are  small  holes,  kept  closed  by  caoutchouc  valves 
when  colza  is  used,  but  when  mineral  oil  is  burned  the 
holes  are  opened  and  the  oil  is  maintained  at  that  height. 

Both  the  exterior  and  interior  deflectors  are  readily  re-  flc^t™sVal  °f  de" 
moved  for  the  purpose  of  trimming  the  wicks. 

The  "buttons"  and  "tips"  are  the  same  for  all  sizes  ofButton8amltiP5r 


. 


78  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

lamps,  their  number  corresponding  to  the  order  of  the  lamp, 
i.  e.j  the  "tip"  and  "button"  of  a  one- wick  lamp  is  appli- 
cable to  the  inner  wick-case  of  a  two,  three,  four,  five,  or 
six  wick  lamp,  and  a  tip  of  any  specified  number  will  fit  the 
corresponding  wick-case  of  any  order  of  lamp. 
zone  of  maxi-  Mr.  1  ouglass  states  that  a  notable  feature  in  the  flames 

mum  intensity. 

of  the  improved  lamp  is  the  increased  power  of  the  beam  in 
the  direction  of  the  sea-horizon  over  that  from  an  old  one 
of  the  same  initial  power,  such  increase  being  due  to  the 
narrow  zone  of  maximum  intensity  found  in  the  flame  of 
the  new  burner,  and  which  is  fully  utilized  for  tbe  longest 
range  by  the  refracting  portions  of  dioptric  apparatus.  In 
the  old  flames  the  zone  of  maximum  intensity  does  exist, 
but  the  difference  in  power  between  it  and  the  portions  of 
the  flame  of  minimum  intensity  is  not  great. 
Adoption  of  This  level  of  maximum  intensity,  shown  at  h  Ti  in  Plate 

muVmLtefnsTtyX1"IV,  is  now  being  adopted  by  the  Trinity  House  for  the  sea- 
horizon  focus  of  the  refractors  of  dioptric  apparatus  and  its 
height  above  the  tips  of  the  burners  in  the  several  lamps 
is  as  follows : 

Millimeters. 
Height  above  Burner  of  one  wick 13 

burned  c    the  B timer  of  t wo  wicks 14 

Burner  of  three  wicks 15 

Burner  of  four  wicks 16 

Burner  of  five  wicks .  > - 17.  5 

Burner  of  six  wicks 19 

Gain  to  light  at     With  these  adjustments  of  the  foci  some  light  is  neces- 

the  zone  of  max-  . ,        ,  -, .       ,    .  -, 

irnum  intensity,  sarily  cut  off  from  the  lower  catadioptric  prisms  by  the 
u  exterior  deflector,"  but  the  increase  of  light  from  the  re- 
.fractor  is  very  great,  it  having  been  found  that  the  power 
of  the  light  sent  to  the  sea-horizon  or  maximum  range  is 
from  25  to  30  per  cent,  more  than  can  be  obtained  from  one 
of  the  old  flames  ;  that  is  to  say,  by  taking  two  flames,  one 
old  and  one  new,  of  the  same  total  initial  candle-power  as 
measured  by  the  photometer,  the  beam  of  maximum  in- 
tensity in  the  direction  of  the  sea-horizon  from  a  dioptric 
apparatus  with  the  new  flame  in  focus  will  be  25  to  30  per 
cent,  greater  than  with  the  old  flame. 

Gas-burner.  I  was  shown  a  new  kind  of  gas-burner,  an  invention  of 
Mr.  Douglass.  The  top  is  perforated  with  a  circle  of  very 
small  holes,  and  this  is  combined  with  a  perforated  button 
similar  to  that  used  for  the  oil-lamp  for  light-houses.  Out- 
side is  placed  the  adjustable  jacket  or  cone,  and  the  ad- 
justable chimney  is  also  used. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


79 


The  light  from  this  gas-burner,  which  is  shown  in  Fig. 
2,  was  not,   in   the   experiments  at 


Fijr.  2. 


Douglass  Gas-burner. 


BlackwaU,  equal  to  that  from  either 
colza  or  mineral  oil,  on  account  of  the 
inferior  quality  of  the  gas  at  that 
place,  but  I  was  told  that  it  was  a 
marked  improvement  over  the  com- 
mon gas-burner. 

Mr.  Douglass  told  me  that  the  power  Actual  power  of 
of  this  Argand  gas-burner  when  burn-  £as-burcer- 
ing  London  gas  of  sixteen  candles  is 
about  the  same  as  that  of  the  Argand 
oil- burner,  viz,  twenty- three  candles, 
and  the  consumption  of  gas  is  about 
30  per  cent,  less  than  the  best  burner 
before  used  in  England. 

The  buttons  for  the  gas-burner  when    Buttong  when 
made  of  brass  last  but  a  little  while,  made  of  brass 

soon  destroyed. 

They  have  been  made  of  platinum, 
but  this  is  expensive,  and  when  I  last 
heard  from  Mr.  Douglass  he  was  ex- 
perimenting with  buttons  made  of 
lava,  which  promised  good  results. 
He  states  that  there  is  no  difficulty  in 
producing  a  gas-burner  of  the  size  of 
the  six- wick  oil-lamp,  or  even  larger,  «ze  of  a  six-wick 

'  lamp  easily  pro- 

on  the  same  principle.  One  of  five 
rings  of  flame  has  been  tried,  and  the 
illuminating  power  is  precisely  the 
same  as  with  the  small  burners  pro 
rata  of  gas  consumed. 
The  following  extract  from  a  letter 


Lava  proposed. 


Gas-burner  the 


of  recent  date,  written  me  by  Mr.  Douglass,  may  prove  of   Extract  from 

,  letter  concerning 

importance  to  us  in  the  future,  and  1  here  place  it  on  record :  a  recently. pat- 

.   ,          ,  .    ,       en  ted  gas-burner. 

"  I  have  just  found  that  a  patent  has  been  taken  out  by 
Mr.  Silber  (the  patentee  of  a  mineral-oil  burner)  for  a  gas- 
burner  nearly  identical  with  my  own,  but,  fortunately,  the 
date  of  the  patent  is  nearly  a  month  after  I  reported  to  the 
Trinity  House  the  results  of  experiments  made  with  burners 
I  had  made  for  some  new  light-houses.  It  is  probably 
important  that  you  know  this,  as  it  is  not  unlikely  that  a 
patent  has  been  taken  out  for  the  burner  in  America.  I 
will  send  you  a  copy  of  the  paper  as  soon  as  it  is  published." 

As  I  have  before  remarked,  the  light-house  establishments    increase  of 

_  T,  powerof  light  and 

of  Europe  have  greatly  increased  the  power  of  their  lights  decrease  of  ex- 
penses. 


so 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


with  a  concurrent  decrease  of  expense,  changes  which  have 
been  produced  by  the  introduction  of  mineral-oil  and  the 
improvements  in  burners. 

Report  of  Mr.  I  can  best , illustrate  this  important  subject  by  quoting- 
one  of  the  earliest  reports  in  regard  to  this  matter  made  by 
Mr.  Douglass  to  the  Trinity  House,  dated  30th  of  March, 
1871,  which  I  find  in  a  "  Eeturn  to  an  Order  of  the  House  of 
Commons  dated  26th  of  June,  1870,  for  a  copy  of  <  Corre- 
spondence between  the  general  light-house  authorities  and 
the  Board  of  Trade,  relative  to  proposals  to  substitute  min- 
eral oils  for  colza  oil  in  light-houses.'" 

"  TRINITY  HOUSE,  March  30, 1871. 
u  Eeferring  to  the  various  and  lengthened  experiments 
which  have  been  made  at  this  House  for  the  purpose  of  de- 
termining the  suitability  of  paraffine  and  petroleum  oils  for 
the  illumination  of  light-houses,  and  the  most  efficient  lamp 
for  consuming  these  mineral  oils,  I  now  beg  to  submit  the 
following  report : 

samples  of  oils  "  For  the  purpose  of  ascertaining  the  relative  merits  of 
paraffine  and  petroleum  oils,  a  sample  of  the  best  burning 
paraffine  was  obtained  from  Messrs.  Young  &  Co.,  and  sam- 
ples of  the  best  burning  petroleum-oil  were  obtained  from  two 
respectable  manufacturers  of  that  article.  The  samples  were 
as  follows,  viz : 


C  o  m  p  a  rative 
table. 


Specific 
gravity. 

Flashing- 
point. 

Net  price  per  gallon. 

Messrs.  Young  &  Co.'s  paraffine-oil  
Trinidad  Petroleum  Company's  petro- 
leum-oil. 

.811 
.820 

136° 
130° 

Is.  6d. 
Exact  price  not  stated  ; 
said  to  be  about  2s. 

Carless,  Capel  &  Co.'s  petroleum-oil  

.796 

116° 

2s. 

Kesult  of  trial 
in  ordinary  lamp. 


Colza  used. 


First  e  x  pe  r  i 
meats. 


"It  was  found  that  the  three  samples,  when  consumed  in 
an  ordinary  single-wick  paraffine  lamp,  gave  nearly  the 
same  photogenic  results ;  and,  being  fairly  equal  as  to 
safety,  the  paraffine  of  Messrs.  Young  appeared,  on  the 
score  of  economy,  to  be  the  most  desirable  material  for  the 
purpose ;  it  was  therefore  decided  to  carry  out  all  further 
experiments  with  this  oil. 

"The  colza-oil  used  in  the  experiment  was  taken  from  the 
corporation's  stock  at  Black  wall ;  it  had  a  specific  gravity 
of  .915,  and  was  of  excellent  quality  for  illuminating  pur- 
poses. 

"The  first  experiments  were  made  by  consuming  the  oil 
in  the  ordinary  Trinity  House  Argand  single- wick,  and 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


81 


first-order  four- wick  lamps  for  colza-oil.  No  alteration  of  the 
lamps  was  found  to  be  necessary  to  effect  this,  but  the  best 
result  was  found  to  be  obtained  when  the  surface  of  the  oil 
in  the  wick-case  was  lowered  somewhat  below  tbe  level  of 
the  tip  of  the  burners.  A  good,  bright,  steady  flame  was 
maintained  in  each  lamp,  and  the  following  are  the  results: 
"  In  recording  these  results,  the  photometric  value  of  each 
light  is  expressed  in  English  units  or  standard  sperm  can- 
dles consuming  120  grains  per  hour.  The  value  of  colza-oil  value  of  colza, 
is  the  contract-price  for  this  article  for  the  current  year, 
(3s.  4:d.  [S3  cents]  per  gallon,)  and  the  value  of  paraffine  is 
the  contract-price  of  Messrs.  Young  for  the  current  year,  (Is. affine- 
6d.  [37  J  cents]  per  gallon:) 

Argand  turner— Paraffine  and  colza  oils. 


Value  of  par- 


Lamp  consuming 
paraffine. 

Lamp  consuming 
colza-oil. 

Illuminating  power  of  tho  light    

8.  4  units 

13.  9  units. 
.  0115  gallon.             Result  with  tho 
.  00083  gallon.        Argand  burner. 
.  460rf. 
.  033d. 

Consumption  of  oil  per  burner  per  hour  

.  0130  gallon  
.00123  gallon  
lS6d 

Consumption  of  oil  per  unit  of  light  per  hour  
Cost  of  light  per  burner  per  hour 

Cost  of  light  per  unit  per  hour 

.022c? 

First-order  four-wick  burner — Paraffine  and  colza  oil. 


Lamp  consuming 
paraffine. 

Lamp  consuming 
colza-oil. 

Illuminating  power  of  light  

209.  7  units  .   .  . 

269.  0  units. 

Consumption  of  oil  per  burner  per  hour  
Consumption  of  oil  per  unit  of  light  per  hour  
Cost  of  )  ight  per  burner  per  hour  
Cost  of  light  per  unit  per  hour  

.20760  gallon.... 
.00099  gallon.... 
3.  13d  

.QlSd 

.  25824  gallon. 
.  00096  gallon. 
10.  33d. 
.  038d. 

Eesult      with 
four  wick  burner. 


"  In  these  experiments  the  lamps  were  kept  burning  for 
six  hours  without  any  trimming  of  the  wicks ;  the  illumi- 
nating power  of  the  lights  was  determined  every  hour  by  a 
Bunsen's  photometer,  and  the  powers  given  are  a  mean  of 
those  powers. 

"The  first  lamp  improved  was  the  single-wick  or  Ar-  improvement 
gaud ;  the  alterations  effected  to  this  lamp  were  as  follows,111 
viz :  The  tips  of  the  wick-case  were  closed  so  as  to  fit  more 
closely  to  the  wick,  and  beveled  for  the  purpose  of  admit- 
ting the  ascending  currents  of  air  freely  to  the  lower  part 
of  the  flame ;  a  perforated  button  was  introduced  at  the 
center  of  the  burner ;  the  wick-case  was  lengthened  for  the 
purpose  of  economizing  the  consumption  of  wick,  and  an 
alteration  was  made  in  the  form  of  the  glass  chimney.  The 
results  of  a  six  hours'  trial  with  this  improved  burner, 
S.  Ex.  54 6 


82  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

which  has  now  been  in  use  at  the  Milford  leading-lights 
for  the  last  three  months  with  good  practical  results,  are  as 
follows : 

Improved  Argand  burner. 


Result  with  im- 
proved Argand 
burner. 


Lamp  consum- 
ing paraffine. 

Lamp  consum- 
ing colza-oil. 

Illuminating  power  of  the  light  

20.  6  units. 

13  9  units. 

Consumption  of  oil  per  burner  per  hour  
Consumption  of  oil  per  unit  of  light  per  hour  .  .  . 

.  0109  gallon. 
.  00053  gallon. 
IQGd 

.  0115  gallon. 
.  00083  gallon. 
461d 

Cost  of  light  per  unit  per  hour 

:  O09d. 

033d 

"  The  above  experiments  with  this  lamp,  as  now  improved, 
show  the  comparative  cost  of  light  produced  by  colza-oil  and 
paraffiue  to  be  as  33  to  9, 11  to  3,  or  55  to  15.    (See  tables.) 
inImfPoTre-wick     "  The  experiments  with  the  Argand  burner,  which  had  been 
burner.  so  successful,  were  followed  by  similar  experiments  with  the 

first-order  or  four- wick  burner.  The  alterations  effected  to 
this  burner  were  as  follows,  viz  :  The  tips  of  the  wick-cases 
were  closed  so  as  to  fit  closely  to  the  cotton  wicks,  and  were 
beveled  in  the  same  manner  as  the  Argand  lamp,  for  the 
purpose  of  admitting  the  ascending  currents  of  air  freely  to 
the  lower  part  of  each  ring  of  flame ;  and  the  wick-cases 
were  considerably  lengthened  for  the  purpose  of  economiz- 
ing the  consumption  of  cotton-wick.  Glass  chimneys  of 
various  forms  were  tried,  but  no  better  result  has  been  ob- 
tained than  with  the  chimney  usually  used  with  the  four- 
wick  burner  for  consuming  colza-oil.  After  a  series  of  trials 
it  was  found  that  the  best  photogenic  result  was  obtained 
with  the  surface  of  the  oil  in  the  wick-case  three  inches 
below  the  tips  of  the  burner  ;  it  was  therefore  necessary  to 
keep  the  oil  uniformly  at  this  level  during  the  burning  of 
the  lamp,  which  was  done  by  placing  at  a  short  distance 
from  and  level  with  the  burner  one  of  the  flow-regulating 
cisterns  formerly  used  for  light-house  lamps,  which  receives 
from  an  upper  reservoir  a  supply  of  oil,  and  maintains  the 
supply  to  the  burner  at  the  required  level  by  a  self-acting 
ball-cock.  I  have  devised  another  and,  in  my  opinion,  a 
more  perfect  arrangement  for  regulating  the  flow  of  oil  in 
these  lamps,  which  has  been  tried  with  perfect  success. 
oil-regulator.  "  I  be^  to  submit  herewith  drawings  of  the  improved  Ar- 
gand and  first-order  four-wick  lamps,  on  the  latter  of  which 
is  the  self-acting  regulator.  This  regulator  consists  of  a 
stand-pipe  placed  at  the  side  of  the  burner ;  the  top  of  this 
pipe,  which  is  open,  is  at  the  level  at  which  the  oil  is  in- 
tended to  flow  in  the  wick-cases  j  a  portion  of  the  supply  of 
oil  from  a  reservoir  placed  above  the  level  of  the  burner,  or 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  83 

from  the  cylinder  of  a  pressure  lamp,  flows  up  the  stand- 
pipe  and  overflows  at  the  top,  descending  by  another  pipe 
surrounding  the  stand-pipe  to  a  cistern  below  the  burner. 
A  glass  thimble  is  screwed  on  to  the  top  of  the  regulator, 
through  which  the  state  of  the  flow  can  be  observed.  The 
necessary  adjustments  of  supply  are  made  from  time  to  time 
by  the  ordinary  regulating- valve  placed  in  the  supply-pipe* 
below  the  burner.  The  tops  of  the  inner  and  outer  tubes  of 
the  stand-pipe  are  rendered  telescopic  by  a  piece  of  pipe 
fitted  to  and  sliding  on  them  externally ;  by  means  of  these 
sliding  pieces  the  flow  of  the  lamp  can  be  altered  at  any 
time  so  as  immediately  to  adapt  it  for  burning  any  descrip- 
tions of  hydrocarbon.  As  the  invention  appears  to  me  to 
be  of  importance  for  regulating  the  flow  of  all  lamps  used 
for  burning  mineral  oils,  I  have  had  it  provisionally  pro- 
tected. 

"As  it  is  found  to  be  necessary  in  burning  paraffine  that 
its  level  in  the  wick-case  be  considerably  below  the  top  of 
the  burner,  it  may  reasonably  be  expected  that  the  tips  of 
the  burners  will  be  destroyed  by  the  heat  of  the  flame  much 
sooner  than  with  burners  consuming  colza-oil,  where  the 
latter  is  constantly  overflowing  the  burners  and  keeping 
them  cool.  I  have  provided  for  this  increased  destruction  of 
burners  by  fitting  each  with  removable  tips,  as  shown  on  Removable  tips. 
the  accompanying  drawings.  With  this  arrangement,  and 
by  keeping  a  supply  of  spare  tips  at  each  station,  the  tips 
of  the  burners  may  be  renewed  at  any  moment  by  the  light- 
keeper  in  charge,  thereby  avoiding  the  necessity  for  return- 
ing the  burner  to  the  workshops  for  repairs. 

"  The  following  are  the  mean  results  of  several  six-hour 
experiments . 

Improved  first-order  four-wick  burner. 


Lamp  consuming 
paraffine. 

"TEST- 

Illuminating  power  of  lifht         

280  units 

269  units. 

Consumption  of  oil  per  burner  per  hour  
Consumption  of  oil  per  unit  of  light  per  hour  

.23240  gallon.... 
.00063  gallon.... 
3  81d 

.  25824  gallon. 
.  00096  gallon. 
9  02d 

Cost  of  lio'ht  per  unit  per  hour 

033d 

lamp. 


"  The  above  experiments  with  this  lamp,  as  now  improved,  cost  <J?c<5za  ami 
show  the  comparative  cost  of  light  produced  by  colza-oil pa 
and  paraffine  when  consumed  in  a  first-order  burner  to  be  as 
38  to  15.    From  these  results  it  will  be  observed  that  the 
superiority  in  illuminating  power  of  the  paraffine  over  the 


84 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


colza  oil  is  much  greater  when  consumed  in  the  Argand 
burner  than  when  consumed  in  the  large  four- wick  burner ; 
consequently  the  contrast  between  the  cost  of  light  pro- 
duced by  the  two  oils  is  greater  when  the  oils  are  consumed 
in  the  Argand  burner  than  when  consumed  in  the  four- wick 
burner. 

*  "  Further  experiments  were  made  for  ascertaining  the 
relative  illuminating  power  of  the  paraffine  and  colza  lamps 
during  the  time  required  at  a  light-house  on  the  longest 
winter  night.  Each  lamp  was  kept  burning  for  sixteen 
hours  without  any  trimming  of  the  wicks,  and  the  following 
are  the  photometric  results  of  several  experiments  : 


IMPROVED  ARGAXD  BURNER. 

IMPROVED  FIRST-ORDER  FOUR-WICK 
BURNER. 

Hours. 

Paraffine  lamp. 

Colza  lamp. 

Hours. 

Paraffino  lamp. 

Colza  lamp. 

1 

Units. 
20.6 
20.6 
20.6 
20.6 
20.4 
20.4 
20.0 
20.0 
19.6 
19.6 
19.2 
19.0 
18.7 
18.6 
18.5 
18.5 

Units. 
13.9 
13.9 
13.9 
13.9 
13.6 
13.3 
12.7 
12.7 
12.7 
12.7 
12.7 
12.3 
12.1 
12.0 
11.9 
11.8 

12.8 

1 

Units. 
280 
274 
280 
278 
278 
278 
274 
277 
271 
266 
265 
277 
267 
266 
256 
250 

Units. 
269 
263 
261 
246 
249 
242 
235 
246 
240 
2:54 
232 
.     227 
233 
224 
230 
200 

2  

2-.         .                      ... 

3 

3 

4 

4 

5  

5  

6 

6 

7 

1 

8  

8  

9 

9 

10 

10      

11  

11  ;  

12 

12 

13 

13    

14 

14 

15 

15 

16  

16  

Mean 

Mean 

19.7 

271 

239 

Deductions.  "  From  these  results  it  is  apparent  that  the  paraffine  lamps 
will  burn  throughout  the  longest  winter  night  in  this  coun- 
try without  any  trimming  of  the  wicks,  and  give  during 

Sustained  inten- this  time  a  light  of  nearly  uniform  photometric  value.  At 
the  end  of  sixteen  hours  the  illuminating  power  of  the 
Argand  lamp,  burning  paraffine,  was  only  10  per  cent,  less, 
and  in  the  four-wick  lamp  only  10.7  per  cent,  less,  than  at 
the  commencement  of  the  trials,  while  the  illuminating 
power  of  the  lamps  burning  colza-oil  gradually  decreased 
soon  after  the  commencement  of  the  trials,  and  at  the  end 
of  sixteen  hours  the  illuminating  power  was  reduced  15.1 
per  cent,  in  the  Argand  burner,  and  25.6  per  cent,  in  the 
four- wick  burner. 

state  of  wicks.  "At  the  termination  of  these  trials  the  wicks  of  the  par- 
affiue  lamps  were  not  much  fatigued ;  the  tips  were  charred 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  85 

only  one-eighth  of  an  inch  in  depth,  and  to  all  appearances 
the  lamp  was  fit  for  burning  many  hours  longer.  The  wicks 
of  the  colza-lamp  were  much  distressed;  they  were  charred 
five-sixteenths  of  an  inch  in  depth,  and  evidently  nearly 
worn  out  ;  trimming  would  have  been  absolutely  necessary 
if  burned  for  three  or  four  hours  longer. 

"  In  conclusion,  it  may  be  generally  stated  as  the  result 
of  the  lengthened  experiments  which  have  been  made  at 
this  House  with  paraffine  as  an  illuminant  for  light-houses' — 

"  1st.  The  cost  of  light  is  72.7  per  cent,  less  ichen  produced    comparative 
by  the  Argand  or  single-icicle  lamp,  and  60.5  per  cent,  less 
when  produced  in  the  first-order  or  four-wick  lamp,  than  colza- 
oil. 

"  2d.  The  lamps  burning  paraffine  ivill  give  a  light  of  more    Paraffine  light 
uniform  illuminating  power  throughout  the  night,  icithout  trim- ra< 
ming,  than  the  lamps  burning  the  colza-oil. 

"3d.  The  lamps  burning  paraffine  are  more  readily  ignited  ;    Paraffine  lamps 
they  burn  icith  greater  certainty,  and  require  less  attention  than ea 
lamps  burning  colza-oil 

u  4th.    The  lamps  burning  paraffine  may  be  arranged  for    increase  ot 
increasing  the  poicer  of  the  light  when  the  state  of  the  weather  po 
requires  it,  as  is  now  done  with  the  electric  light  and  coal-gas. 

"  5th.  Paraffine  can  be  stored  and  used  at  light-houses  with    paraffinc  may 
safety,  provided  that  ordinary  care  is  used.  safety rcd  wltU 

"  I  am,  &c., 

"JAS.  N.  DOUGLASS." 

The  tables  given  in  the  foregoing  report  showed — 

1st.  That  light  for  light  with  a  first-order  lamp,  the  cost    Cogt  with  first. 
of  the  paraffine  was  about  one-half  that  of  the  colza  light.         or%der  lamp- 

2d.  Light  for  light  with  the  fourth-order  lamp,  the  cost  of    Cost    with 
paraffine  teas  about  one-fourth  that  of  colza.  fourth-order 

These  results  were  confirmed  by  a  comparison  of  the  fig- 
ures in  the  following  table  of  results  obtained  by  Dr.  Mac-  Confirmation  of 
adam,  scientific  adviser  of  the  board  of  commissioners  of 
northern  (Scottish)  lights,  Mr.  Douglass,  engineer  of  the 
Trinity  House,  and  Professor  Tyndall,  scientific  adviser  of 
the  Trinity  House,  by  quite  separate  and  distinct  experi- 
ments. 


86 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Comparative  statement  of  experiments  for  testing  the  values  of  colza  andpar- 
affine  as  illuminants  for  light-houses. 


Dr.  Macadam. 

Mr.  Douglass. 

Dr.  Tyndall. 

<s 
,2 

o 

o 

© 

c 

1 

dt 

£ 

"o 

u 

<s 

« 

1 

i 

§ 

1 

292.  93 
2.134 
.2226 

.  00076 
4.01 
.  013 

51.85 

18.49 
58.9 
.  01335 

.  00072 
.  2402 
.013 

75.47 

FIRST-ORDER  LAMP  : 
Illuminating  power  of  light  expressed 
in  standard  candles,  consuming   120 
grains  per  hour 

261.3 

261.3 

269. 

280. 
4  09 

284.  85 

Percentage  of  increase  of  light  in  favor 
of  paraffi  ue 

Consumption  of  oil  by  the  lamp  during 
one  hour  in  imperial  gallons  

.2077 

.  00079 
8.30 

.1967 

.  00075 
3.55 

.  2582 

.  00096 
9.02 

.2324 

.  00083 
3.87 
.014 

57.57 

20.6 

48  2 

.1928 

.  00067 
7.71 

.027 

11.63 

Consumption  of  oil  per  caudle  per  hour 
in  imperial  gallons  

Cost  of  light  per  hour  in  pence  

Cost  of  light  per  candle  per  hour  in  pence 
Percentage  of  saving  in  cost  in  favor  of 
paraffiue 

.032 

.014 
56.  25 

19.  83 
75.02 
.0125 

.  00063 
.218 
.011 

76.6 

.033 
13.9 

FOURTH-ORDER  LAMP  : 
Illuminating  power  of  light  expressed 
in  standard  candles,   consuming  120 
grains  per  hour  

11.33 

Percentage  of  increase  of  light  in  favor 
of  paratfine  ... 

Consumption  of  oil  by  the  lamp  during 
one  hour  in  imperial  fallons 

.0133 

00117 
.532 
.047 

.0115 

.  00083 
.461 
.033 

.0109 

.  00053 
.196 
.009 

72.  72 

.0146 

.  00126 
.  6132 
:053 

Consumption  of  oil  per  candle  per  hour 
in  imperial  ""aliens 

Cost  of  light  per  hour  in  pence  ... 
Cost  of  light  per  candle  per  hour  in  pence 
Percentage  of  saving  in  cost  in  favor  of 
paraffino 

The  foregoing  tables  were  among  the  earliest  results  of 
experiments  with  paraffiue  oil  and  petroleum. 

^he  improvements  made  by  Mr.  Douglass  from  time  to 
by  .,  r.  Douglass.  ^jme  jn  lamp-burners  have  resulted  in  what  is  apparently  a 
perfect  light-house  lamp,  which  can  hardly  be  surpassed  in 
economy  and  efficiency  except  by  the  supply  of  pure  oxy- 
gen to  the  flame. 
Details  of  lamp.     Each  of  the  Douglass  lamps  now  made  for  the  English 

light-houses  has — 

Burner-tips.  ist.  A  series  of  burner-tips  so  constructed  that  they  may 
be  removed  when  burned  out,  instead  of  substituting  new 
burners,  as  is  done  under  the  old  system. 

These  "tips,"  which  slightly  compress  the  wicks,  give  to 
them  a  perfectly  cylindrical  form,  and  their  exterior  sur- 
faces being  slightly  conical,  the  air  from  below  is  sent 
directly  into  the  flame  without  danger  of  forming  eddies 
where  the  gases  burn  imperfectly. 

interior  deflect-  2d.  A  curvilinear  perforated  "  button,"  (interior  deflector,) 
which  sends  the  interior  current  of  air  into  the  flame. 

3d.  An  outer  "cone,"  (exterior  deflector,)  by  which  a 
second  current  of  air  is  thrown  into  the  flame  at  its  most 
advantageous  zone. 

4th.  A  space  between  the  cone  and  the  chimney,  by 
which  a  third  or  outer  air-current  is  produced. 


Exterior  deflect- 
or. 


Outer 
rent. 


air-cur- 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


87 


This  air-current  is  injected  into  the  flame  above  that  ad- 
mitted by  the  "  exterior  deflector,"  and  is  for  the  purpose 
of  increasing  combustion.  A  portion  of  this  current  being 
drawn  up  along  the  surface  of  the  chimney,  prevents  the 
heat  from  melting  or  otherwise  injuring  the  glass,  in  which 
a  milkiness  resulting  from  disintegration  sufficient  to  im- 
pair the  light,  is  found  to  be  produced  by  long-continued  heat. 

Another  result  produced  by  this  current  is  that  the  base 
of  the  chimney  is  kept  at  a  degree  of  temperature  suffi- 
ciently low  to  admit  the  removal  of  the  chimney  with  the 
naked  hand,  rendering  the  use  of  tongs  unnecessary. 

5th.  An  adjustable  gallery  by  which  the  chimney  is  raised 
and  lowered  at  will,  it  being  found  that  the  height  of  the 
shoulder  of  the  chimney  has  a  marked  effect  upon  the  flame. 

6th.  Yery  soft  and  compressible  wicks  adopted  for  this 
lamp  only  after  many  repeated  experiments. 

Each  of  these  inventions,  some  of  which  were  original 
with  Mr.  Douglass,  and  some  had  previously  been  in  use, 
is  considered  of  importance,  but  a  combination  of  the  whole- 
is  essential  to  produce  the  remarkable  results  given  in  the 
following  table  deduced  from  the  most  recent  experiments 
of  Mr.  Douglass  and  kindly  sent  me  by  him  since  my  re- 
turn to  this  country : 

Comparative  statements  showing  the  mean  illuminating  power  and  consumption 
of  oil  with  the  old  and  improved  light-house  burners  of  the  Corporation  q, 
Trinity  Rouse. 


Chimney  ko  p  t 
cool. 


Adjustable  gal- 
lery. 


Soft  wick. 


Combination  of 
these  inventions. 


Compar  a  t  i  v  e 


monts  with  Mr. 
Douglass's  burn- 


Old  concentric  burners  con- 
suming colza. 

Improved  concentric  burners  con- 
suming colza. 

Number  of  wicks: 
Full  power  
Half  power 

4 

3 

2 

1 

6 
3 

5.  00 

722 
342 

76.24 
36.12 

.106 
5.5 

5 
3 

4.16 

514 
225 

51.81 

22.68 

.101 
5.0 

4 
2 

3.32 

328 
178 

32.12 
17.43 

.098 
4.5 

°1  93 

3 

2 

2.49 

208 
146 

20.17 
14.16 

.097 
3.2 

24.  55 

29.86 

2 
1 

1.65 

82 
51 

7.87 
4.80 

.096 

2.8 

41.38 

28.57 

1 

.82 

23 

2.20 

.096 
2.2 

65.47 
24.81 

Mean  diameter  of 
outer  wick,  (in 
inches) 

3.32 

2G9 

2.49 
167 

1.65 

58 

.82 
13.9 

Illuminating 
power  of  flame  in 
standard  sperm 
candles,    (or 
units,)  consum- 
ing   120   grains 
per  hour  : 
Full  power  
Half  power 

Consumption  per 
burner  per  hour 
in  fluid-ounces, 
128  to  American 
wine-gallon  : 
Full  power  
Half  power  .  .  . 
Cou  sumption  per 
unit  per  hour  in 
fluid-ounces  
Mean    height    of 
flame,  (in  inches). 
Increased    illumi- 
nating power  of 
improved  burn- 
er, i>er  cent 

39.77 

23.09 

7.79 

1.77 

.148 
3.75 

.138 
2.5 

.134 
2.0 

.128 
1.5 

Saving  in  oil  with 
new  burner  for 
c  no  h    unit    of 
liiiht,  per  cent  . 

33.77 

88  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Consumption  of  An  inspection  of  the  above  table  shows  the  consumption 
of  colza-oil  in  the  new  burner  to  be  very  nearly  one-tenth  of 

unit  used.  an  ounce  for  each  unit  of  light,  that  unit  being  the  light 
from  a  standard  sperm-candle  consuming  120  grains  per 
hour,  and  Mr.  Douglass  informs  me  that  the  improved 

Power  of  ihiht  burners  have  raised  the  power  of  light  produced  from  colza  to 

from  colza   with  ,  .        .     . 

new  burner  equal  such  a  degree  that  this  oil  is  now  practically  equal  in  illu- 

to   that   of   best  ,.  -,  ,. 

mineral-oil.  uiinatiug  power  and  consumption  to  the  best  mineral-oil 
found  in  Great  Britain,  the  latter  having  a  specific  gravity 
ranging  from  .810  to  .820,  flashing  above  130°  Fahrenheit 

tween  cX  and  and  distilling  between  212°  and  572°  Fahrenheit,  so  that 
6  °f  the  difference  between  mineral  and  colza  oil  for  light-house 


illumination  is  principally  one  of  economy.    In  England  the 

Cost  of  colza,   cost  of  colza-oil  is  about  2s.  9d.  (68  cents)  per  imperial  gal- 

Of  minerai-oii.   Ion,  that  of  mineral-oil  of  the  quality  abovp,  stated  being  1,9. 

Id.  (39  cents)  per  imperial  gallon,  so  that  in  that  country, 

for  all  orders  of  light-house  lamps,  the  cost  of  maintaining 

mineral-oil  sea-coast  lights  is  about  one-half  that  of  maintaining 

colza-oil  lights. 

substitution  of     For  this  reason,  as  well  as  because  mineral-oil  lamps  are 

mineral  for  colza  ' 

oil.  much  more  cleanly,  more  easily  lighted,  and  require  no  trim- 

ming during  the  night,  thus  making  their  efficiency  less  de- 
pendent on  the  watchfulness  of  keepers,  the  English  are 
rapidly  substituting  mineral-oil  lamps  in  their  light-houses 
for  those  for  colza  formerly  used. 

Price  of  lard-on.     In  the  United  States  the  average  price  of  our  illumiuant, 

lard  oil.  of  which  we  annually  use  about  100,000  gallons,  is 

post  of  mineral-  89  cents  per  gallon  5  the  cost  of  mineral-oil  of  the  quality 

required  by  the  British  and   French  contract-specifications 

is  about  35  cents  per  gallon. 

The  following  table  gives  the  comparative  values  in  stand- 
ard candles  of  the  new  English  Douglass  and  the  American 
light-house  lamps  : 


6 

5 

4 

3 

2 

1 

English,  lamps  valuo  in  caudles    

722 

514 

328 

208 

82 

23 

210 

133 

44 

15.3 

56 

56 

86 

50 

An  examination  of  the  foregoing  tables  and  the  facts  j  ust 
stated  shows : 

1st.  That  by  the  adoption  of  the  triple  current  of  air  burn- 
ers of  the  English  and  French  into  light-houses,  we  should  gain 
more  than  50  per  cent,  in  the  power  of  our  lights. 

2d.  By  the  adoption  of  American  mineral-oil  instead  of 
the  lard-oil  now  used  in  our  light-houses,  we  should  save  $54,000 
per  annum  in  cost  of  oil. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  89 

This  is  on  the  supposition  that  the  American  refiners  will  pro- 
duce, if  stimulated  by  the  use  of  the  former  by  the  Government, 
an  article  equal  to  that  used  in  Europe  for  light-house  illu- 
mination. 

3d.  If  it  should  be  found  that  such  American  oils  can- 
not be  obtained,  precisely  the  same  excellent  quality  of  mineral- 
oil  ( Scotch)  as  is  used  in  the  liglit-houses  of  France  and  Great 
Britain  can  be  imported  at  a  cost,  including  freight,*  not  exceed- 
ing 30  cents  per  gallon,  and  the  saving  in  this  case  would  not  be 
less  than  $53,000  per  annum  in  cost  of  oil. 

Since  rny  return  from  Europe  the  Trinity  House  has  kindly 
sent  to  the  Light- House  Board  several  improved  four- wick 
burners,  for  both  colza  and  mineral  oil ;  interior  deflectors 
for  cutting  off  one,  two,  or  three  wicks ;  one  Argand  lamp, 
complete,  for  burning  colza  or  mineral  oil;  and  one  Argand 
gas-burner,  as  well  as  a  supply  of  wicks,  chimneys,  &c.,  for 
use  with  the  lamps  and  burners  sent. 

In  regard  to  the  purchase  of  mineral-oil,  I  give  below     specifications 
some  extractsfrom  the  specifications  which  the  Trinity  House  01 
furnishes  to  bidders  : 

u  1.  The  mineral-oil  required  to  be  supplied  under  this  con-    Quality, 
tract  is  to  be  of  the  best  possible  quality,  the  greatest  care 
is  to  be  taken  in  its  preparation,  and  it  must  be  as  free  as 
possible  from  oil  of  vitriol. 

"  2.  If  the  oil  be  petroleum,  it  must  have  a  specific  gravity   specific  gravity 
not  less  than  .785,  nor  greater  than  .790,  at  60°  Fahrenheit ; ifpetl 
its  flashing-point  not  lower  than  125°  to  130°  Fahrenheit, 
and  it  shall  distill  between  212°  and  482°  Fahrenheit. 

"  3.  If  the  oil  be  paraffine,  it  must  have  a  specific  gravity    of  paraffine. 
not  less  than  .810  nor  greater  than  .820  at  60°  Fahrenheit ; 
flashing  above  130°  Fahrenheit,  and  distilling  between  212° 
and  572°  Fahrenheit. 

"  4.  A  sample  of  five  gallons  of  each  of  the  oils  proposed  to    samples. 
be  supplied  is  to  accompany  the  tender ;  such  sample  will  be 
tested  by  burning  to  ascertain  its  action  on  the  wick,  and    Tests. 
its  specific  gravity,  flashing-point,  and  chemical  composition 
(to  be  determined  by  fractional  distillation)  being  ascer- 
tained, the  several  results  shall,  if  approved,  be  considered 
binding  in  all  subsequedt  deliveries  of  oil  under  this  contract. 

u  5.  The  contractor  will  be  furnished  with  tinned  iron  cans   cans  furnished. 
to  hold  the  required  amount  of  oil  for  each  light-house; 

*  The  contract-price  of  oil  in  England  is,  as  stated  above,  Is.  6d.  per 
imperial  gallon,  or  about  39  cents.  The  freight  to  New  York  I  have 
ascertained  will  not  be  over  4  cents,  making  its  cost  here  of  the  im- 
perial gallon  43  cents,  or,  as  this  is  one-fifth  larger  than  the  American 
wine-gallon,  about  36  cents  per  wine-gallon. 


90  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

every  can  will  contain  about  five  gallons,  and  will  weigh 
net  about  21  pounds.  The  cans  will  be  delivered  to  the 
contractor  at  the  Trinity  Buoy-  Wharf,  Black  wall,  in  per- 
fectly tight  and  sound  condition,  and  the  contractor  must 
assure  himself  thereof  at  the  time  of  his  receiving  them,  as 
no  plea  of  unsoundness  will  be  admitted  after  acceptance, 
in  case  of  leakage  or  fracture. 


Test  when  oil  "  8.  Samples  will  be  drawn  at  pleasure  from  any  portion  of 
ed>  each  parcel  delivered,  and  shall  be  tested  in  accordance  with 
the  tenor  of  paragraph  4.  In  the  event  of  the  test  being 
satisfactory,  such  parcel  shall  be  formally  received,  but  if 
not,  the  contractor  shall,  at  his  own  expense,  remove  the 
whole  quantity  within  ten  days  after  receiving  notice  of  re- 
jection, and  must  immediately  replace  the  same  with  another 
supply,  which  latter  shall  be  tested  in  like  manner.  Records 
will  be  kept  of  the  results  in  each  case  of  testing  samples." 
Tests  at  depot.  All  oils  are  thoroughly  tested  twice  :  first  by  the  officers 
of  the  depot  at  Blackwall,  and  afterward  in  samples,  by  the 
engineer  and  Elder  Brethren  at  the  Trinity  House. 

Processof  test-     The  process  of  testing  the  colza-oils  received  from  the  con- 

ing colza. 

tractors  is  thus  described  : 

waders168  from  Each  of  the  parties  tendering  bids  sends  a  sample  of 
twenty  gallons  marked  with  a  letteronly,  so  that,  while  test- 
ing, the  manipulator  has  no  knowledge  of  whose  oil  is  under 
test.  A  sample  of  the  previous  year's  supply  is  also  intro- 
duced with  the  others  ;  of  the  identity  of  this  also  the  ma- 
nipulator is  ignorant. 
Special  quaii-  ^ne  °^s  are  tested  with  regard  to  the  consumption  ;  the 

ties  required.      effect  of  combustion  upon  the  wick  5  the  illuminating  power 

and  specific  gravity  5  also  with  regard  to  congelation. 
Lamps  used.  For  consumption  and  combustion,  the  samples,  including 
that  of  the  previous  year's  supply,  are  tried  in  Argand  lamps 
kept  burning  for  sixteen  hours,  that  being  considered  as 
about  equal  to  the  longest  winter  night.  During  this  time 
particular  notice  is  taken  of  any  diminution  of  the  flame, 
(which  must  be  kept  1J  inches  high,)  or  any  other  irregularity 
of  combustion,  and  at  the  expiration  of  the  time  the  residue 
in  each  lamp  is  carefully  measured  to  ascertain  the  exact 
quantity  consumed. 
Measure  of  iiiu-  The  illuminating  power  of  each  oil  is  measured  bv  a  pho- 

Tninating  power. 

tometer,  (Buusen's,  used  also  in  our  service,)  and  the  unit 
is,  as  with  us,  the  standard  candle  consuming  120  grains  per 
hour.  The  observation  is  taken  at  the  full  power  of  the 
light  when  first  lighted,  and  again  at  the  end  of  the  trial  . 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


91 


The  specific  gravity  of  each  oil  is  measured  by  an  ole-    Measure  of 

gravity. 

ometer  in  the  usual  way. 

To  ascertain  with  regard  to  congelation,  samples  of  each    congelation. 
oil  are  placed  in  half-pint  clear  glass  bottles  and  subjected 
to  a  temperature  of  25°  Fahrenheit,  at  \vhich  temperature 
they  should  remain  fluid  for  sixteen  hours. 

A  portion  of  the  original  twenty  gallons  supplied  by  the 

, 

firm  who  obtains  the  contract  is  retained,  and  a  sample 
from  every  cask  delivered  by  them  during  the  period  of  the 
contract  is  comparatively  tested  with  the  original  sample. 
Trinity  House  acts  as  agent  for  the  purchase  of  oil  for  the    Trinity  House 


delivered. 


Fig.  3. 


agent  for  foreign 
light-house  es- 
tablishments. 


Storage     capa- 
city at  the  depot. 


Oil-tanks. 


Cocks. 


light-houses  of  some  foreign 
countries  and  of  several  of 
the  English  colonies.  The 
storage  capacity  for  oil  at 
Black  wall  is  about  210  tons, 
(about  54,000  gallons.)  The 
great  cast-iron  tank  for  colza- 
oil  is  divided  into  compart- 
ments, and  is  much  like  our 
oil-tank  at  Staten  Island. 

The  oil  is  drawn  from  two 
levels,  and  it  is  the  universal 
practice  in  the  English  light- 
house service  to  draw  from 
more  than  one  level  wherever 
large  oil-vessels  are  used, 
some  of  the  100-gallou  oil- 
butts,  having  as  many  as  three 
cocks  at  different  heights. 

The  level  of  the  oil  in  each 
tank  is  shown  by  means  of  a 
float  attached  to  a  chain, 
which  passes  over  a  pulley  at 
the  top,  to  a  weight  moving 
upon  a  graduated  scale  on  the 
outside.  The  oil  is  emptied 
into  the  tanks  through  pipes 
leading  from  the  floor  above,  Five-gallon  oil-can, 

and  is  delivered  from  the  tanks  for  issue  to  the  light-houses 
into  sheet-iron  "drums"  (cans)  holding  five  gallons  each,  and    Five-gallon 
which  are  11  inches  in  diameter  and  15  inches  in  height.      cans' 

A  recess,  made  by  sinking  the  top  below  the  sides,  con- 
tains the  handles  a  a,  (see  Fig.  3,)  and  a  screw-plug  for 
emptying. 

These  cans  are  purchased  by  contract,  but  are  tinned  caJ8urc h a8e  of 


Float  to  show 
oil-level. 


92 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Machine-shop. 


on   the  inside  by  the  workmen  at  the  depot.     They  are 
in  size  and  construction    admirably  designed   for  trans- 
port.   Three  of  them  can  be  easily  carried  by  two   men, 
and  they  stow  in  the  supply- vessels  and  boats  -with  little 
Plan  of  delivery loss  of  space.     They  are  also  strong  and  durable.    I  think 
^aa^hj^  it  a  better  plan  for  delivering  oil  to  light-houses  than  ours 
of    shipping  it  in  barrels  on  the    eastern    coast    and    in 
square  tin  cans  to  the  Pacific  coast  light-houses. 

^Lamp-chim-  Especial  attention  is  paid  to  the  testing  of  lamp-chim- 
neys, which  are  distributed  to  the  light-houses  from  Black- 
wall  depot. 

A  gauge,  &,   of   metal  is  fastened  to  a  frame,  a,  (see 
Fig.  4,)  in  which  the  chimney  is  placed,  and  its  accuracy 
Fig.  4.  of  shape  and  thickness  is  deter- 

mined by  turning  it  around  its  axis. 
Those  which  do  not  fit  the  gauge 
closely  are  rejected. 

The  machine-shop  is  well  fitted  up 
with  machinery,  including  lathes, 
drilling  and  screw  -  cutting  ma- 
chines, and  all  kinds  of  work,  ex- 
cepting heavy  forging  and  casting 
of  iron,  are  done  here;  even  the 
manufacture  of  the  furniture  used 
in  the  light-house  towers  and  keep- 
ers7 dwellings. 

Among  great  varieties  of  work 
I  saw  constructing  in  the  smith- 
ery  a  lantern  for  a  light-ship,  made 
entirely  of  iron,  the  sash-bars  being 
Chimney-gauge.          of  malleable  cast  iron. 

Lampstrimmed  This  lantern  was  not  intended  to  be  lowered  to  the  deck 
Stern!  m  Qg  for  trimming  the  lamps,  as  is  usual,  but  was  designed  to  re- 
main in  its  place  on  the  mast,  which  is  to  be  of  hollow  steel 
about  two  feet  in  diameter.  Small  doors  open  from  the  hol- 
low of  the  mast  on  to  the  deck,  and  also  into  the  lantern 
when  placed  in  position,  an  inside  ladder  affording  a  means 
of  communication  with  the  lantern  at  all  times. 

There  is  about  20  inches  space  between  the  sides  of  the 
lantern  and  the  reflectors,  to  enable  the  keepers  to  trim  the 
lamps,  and  an  outside  foot-rail  is  provided  to  enable  them  to 
clean  the  exterior  of  the  lantern-glass. 

Question  of     Whether  so  heavy  a, mast  and  lantern  can  be  carried  on 
in  all  weathers  is  yet  a  matter  of  experiment, 


Lantern  for 

ght-sliip. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  93 

but  there  can  be  no  doubt  that  facility  of  trimming  without 
lowering  the  lantern  is  much  to  be  desired. 

There  was  also  constructing  a  set  of  machinery  for  a  fog- 
bell,  the  driving- weights  of  which  were  square  and  furnished 
with  rollers  on  the  sides  to  avoid  friction  against  the  boxes. 

Above  the  buoy-shed  is  a  convenient  photometric  gallery 
for  testing  lamps,  oils,  and  lenses.     It  is  about  80  by  12  sallery- 
feet,  the  interior  is  painted  black,  and  the  sky-lights  are  so 
arranged  that  all  daylight  can  be  excluded. 

At  Blackwall  is  always  kept  a  light-ship  for  relief  in  case    Relief  light- 
of  accident  to  any  of  the  numerous  light-ships  on  the  coast 
near  the  Thames,  and  this  is  also  the  place  of  repair  not 
only  for  these  vessels  but  for  the  steam-tenders. 

Trinity  House  ceased  some  years  ago  to  build  iron  light-    ir0n  light-ships 
ships,  on  account  of  their  fouling  so  rapidly  and  the  conse-  g>°r8idered  illte' 
quent  necessity  of  bringing  them  into  port  once  in  two 
years,  while  the  wooden  light-ships  require  to  be  brought  in 
but  once  in  seven  years.     Further  reasons  for  giving  up  the 
use  of  iron  light-ships  are  that  they  are  cold  and  damp,  and 
when  run  into,  sustain  much  more  danger  than  the  wooden 
vessels. 

The  approximate  cost  of  a  light-ship,  either  of  iron  or    cost  of  light- 
wood,  including  everything,  is,  in  England,  £5,500,  or  about shlp' 
$27,500. 

The  size  of  English  light-ships  is  about  the  same  as  our    size, 
own,  although  the  latter  have  much  greater  beam  and  depth 
of  hold,  and  are  more  rounded  at  the  sides,  which  probably 
enables  them  to  ride  easier  and  with  less  shock  to  the  catop- 
tric apparatus  and  the  lantern. 

Those  placed  in  exposed  situations  are  usually  held  by    Moorings, 
single  mushroom- anchors,  weighing  two  tons,   and  each 
light-ship  has  210  fathoms  of  1  J-iuch  cable. 

The  Seven  Stones  light-ship,  oft'  Land's  End,  is  anchored  u  Anchors  of  the 
in  42  fathoms  of  water  and  has  315  fathoms  of  cable  attached 
to  her  mushroom. 

In  addition  to  these  moorings  every  light-ship  has  on    Additional 
board  spare  anchors  and  cables  in  readiness  to  be  let  go  at anchors- 
a  moment's  notice  in  case  the  vessel  should  drag  her  anchor, 
but  such  an  occurrence  has  not  happened  for  several  years. 

The  chain-cables  used  by  all  the  vessels  of  the  Trinity    chain-cahies: 
House  are  made  with  great  care1.    The  requirements  and  the  S"rac™enti 
mode  of  testing  are  as  follows : 

All  the  cables,  mooring-chains,  rigging  and  crane  chains,    Quality   of 
and  articles  appertaining  thereto,  excepting  the  stay-pins 
and  steel  pins,  are  manufactured  from  fine  fibrous  iron  of  ap- 
proved quality,  and  must  bear  a  tensile  strain  of  not  less  than 


94  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

23  tons  per  square  inch  of  original  area,  with  a  contraction 
at  fracture  of  not  less  than  45  percent,  of  the  original  area. 
Pfisality  of  8tay"  The  cast  iron  in  stay-pins  is  of  the  best  tough  gray  metal, 
and  must  bear  a  cornpressive  strain  of  not  less  than  52  tons  per 
square  inch  of  original  area,  with  a  reduction  in  length  of 
not  less  than  10  per  cent. 

steel  pms.  The  steel  pins  for  retaining  the  joining  shackle-bolt  are 

of  the  best  and  toughest  manufacture,  and  must  bear  a 
tensile  strain  of  not  less  than  35  tons  per  square  inch  of 
original  area,  with  a  contraction  at  fracture  of  not  less  than 
45  per  cent,  of  original  area. 

workmanship.  All  cables,  mooring-chaius,  rigging  and  crane-chains,  and 
articles  appertaining  thereto,  are  required  to  be  of  the  best 
possible  workmanship.  They  are  proved  at  a  proving-ma- 
chine,  licensed  by  the  Board  of  Trade,  at  the  expense  of  the 
contractor,  and  the  proving  is  carried  out  in  the  presence 
of  the  engineer  or  other  designated  officer. 

Proof-strains     The  chains  are  subjected  to  the  following  proof- strains, 

for     testing 

chains.  viz :  Open-link  cable  and   moormg-chams,  and  close-link 

rigging  and  crane  chains  are  proved  to  8.47  tons  per  square 
inch  of  each  side  of  the  link,  or  466  pounds  per  circular 
one-eighth  inch  of  the  diameter  of  the  iron,  and  stud-chains 
are  proved  to  11.46  tons  per  square  inch  of  each  side  of  tbe 
link,  or  630  pounds  per  circular  inch  of  the  diameter  of  the 
iron.  Any  links  which  may  appear  to  be  defective  are  cut 
out  and  replaced,  and  the  chain  re-proved  at  the  expense  of 
the  manufacturer.  If  more  than  three  links  are  found  to 
be  defective  in  any  length  after  proving,  such  length  is  con- 
sidered liable  to  rejection.  All  forelock- shackles,  connect- 
ing-shackles, and  spare  swivels,  are  proved  to  the  same 
strain  as  the  chain  with  which  they  are  intended  to  be  used. 
Further  tests  ^n  addition  to  the  above  proof,  and  for  the  purpose  of 
ascertaining  the  exact  quality  of  the  iron  and  welding,  the 
engineer  selects,  as  he  may  think  fit,  from  any  lengths  of 
each  of  the  sizes  of  chain  ordered,  three  test-pieces,  four 
feet  long  of  each  size.  These  pieces  are  cut  out  of  the 
chains,  and,  together  with  a  shackle  of  each  size,  also  selected 
by  the  engineer,  are  stamped  with  a  Trinity  House  stamp, 
and  are  sent  by  the  contractor  to  such  public  testing-works 
as  may  be  designated  by  the  Trinity  House,  to  be  tested 
and  reported  on  by  the  engineer  of  the  Trinity  House, 
at  the  contractors  expense.  The  quality  of  the  iron  is 
ascertained  by  testing  the  iron  in  one  link  cut  off  each 
of  the  pieces  of  chain,  also  the  iron  in  each  of  the 
shackles.  The  remainder  of  each  of  the  four-foot  lengths 
of  chain  is  then  tested  to  ascertain  the  quality  of  the  weld- 
ing, when  the  ultimate  breaking-stress  must  not  be  less 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


95 


than  16  tons  per  square  inch  of  each  side  of  the  link,  or 
880  pounds  per  circular  one-eighth  inch  of  the  diameter  of 
the  iron.  In  the  event  of  these  tests  proving  satisfactory, 
the  lengths  of  chain  from  which  the  test-pieces  were  taken 
are  to  be  made  good  by  the  contractor,  and  the  lengths  re- 
proved at  his  expense.  In  the  event  of  any  portion  of  the 
material  or  welding,  when  tested,  proving  inferior  in  quality 
to  that  specified,  the  chains  and  shackles  are  rejected,  and 
the  above  tests  are  repeated  at  the  expense  of  the  con- 
tractor on  other  pieces  of  chains  and  shackles  selected  by 
the  engineer  in  the  same  manner  from  other  chains  and 
shackles  manufactured  by  the  contractor,  and  submitted  for 
approval. 

At  the  depot  are  a  great  many  buoys  of  all  kinds,  most 
of  them  of  timber,  but  I  believe  none  are  now  made  of  that 
material.  Some  of  the  different  kinds  are  the  "nun,"  ucan  re- 
versed," "can,"  "  egg-bottom,"  "convex  bottom,"  "flat  bot- 
tom," "hollow  bottom,"  "  spherical,"  and  "conical." 

The  English  can-buoy  corresponds  in  shape  to  our 
nun-buoy,  except  that  the  larger  end  is  in  the  air.  The 
cylindrical  buoys  used  by  the  English  are  much  like  our 
can-buoy,  and  are  said  to  satisfy  all  conditions  required. 
An  English  nun-buoy  is  conical  at  both  ends  and  is  used 
to  mark  wrecks.  An  English  flat-bottom  buoy  is,  as  are 
some  of  the  others,  water-ballasted,  i.  e.,  they  have  a  cross 
diaphragm  at  a  proper  distance  from  the  bottom,  and  the 
water  is  allowed  to  flow  in  and  out  of  the  lower  compart- 
ment thus  made  through  eight  holes  an  inch  in  diameter, 
placed  at  equal  distance  around  its  sides.  The  water  can- 
not be  discharged  unless  the  buoy  is  careened  for  some  time, 
and  it  is  therefore  as  completely  ballasted  as  if  the  water 
had  no  means  of  exit. 

When  those  buoys  are  required  for  deep  water  where  the 
weight  of  the  rnooi  ing-chain  is  sufficient  for  ballast,  water- 
ballast  is  not  used,  and  the  holes  are  plugged  with  hard 
wood.  With  the  increased  buoyancy  thus  obtained  the 
same  line  of  flotation  as  in  shoal  water  is  approximately 
attained. 

This  is  a  matter  of  importance,  preserving,  as  it  does,  a 
uniformity  of  appearance  in  each  class  of  buoys,  irrespective 
of  the  depth  of  water  in  which  they  are  moored. 

The  buoys  said  to  be  the  best  for  strong  tideways  are  the 
can,  cylindrical,  and  flat  bottom;  for  exposed  channels  and 
coasts  the  egg-bottom  is  used. 

Another  which  is  used  with  satisfactory  results  is  a  pat-   Herbert's  buoy, 
ent  hollow-bottomed  one,  called  "  Herbert's  "  buoy. 


Buoys. 


Names. 


Can-buoy. 


Cylindrical. 


Nun. 

F 1  a  t  -  b  o  ttom 
water-  ballasting. 


when 


buoys 


Best  buoys  for 


96  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

The  theory  of  the  action  of  this  buoy  is  that  the  air  con- 
fined in  the  bottom  forms  an  elastic  spring  upon  which  the 
buoy  rebounds  in  gentle  and  easy  motions,  causing  but  mod- 
erate friction  to  the  mooring- chain,  little  or  no  pull  upon 
the  sinker,  and  a  corresponding  relief  from  agitation  or  fric- 
tion to  the  globe  and  staff  above. 

size  of  buoys.  I  was  especially  struck  with,  the  great  size  of  some  of  the 
buoys  which  I  saw  at  Blackwall  and  at  other  places,  many 
of  them  being  20  feet  in  length. 

iShbruog80f  En~  Tlie  En£lisl1  ordinarily  moor  their  buoys  by  a  single  chain 
and  sinker  or  mushroom,  but  in  some  instances  double  moor- 
ings are  used.  The  chains  of  light- ships,  after  three  years' 
service  as  such,  are  converted  into  buoy-chains.  The  pro- 
portion of  chain  used  in  mooring  buoys  is  generally  three 
times  the  depth  of  water. 

shifting  buoys.     Small  buoys  are  shifted  twice  a  year,  but  the  buoys  above 
8  feet  remain  at  their  stations  for  two  or  three  years  and 
are  painted  at  their  anchorage  periodically. 
served*  fiTbuoV-     ^e  f°H°wing  *s  the  system  observed  in  buoying  chan- 

ing  English  wa-  nfkjg  • 
ters. 

sides  of  chan.  The  side  of  the  channel  is  to  be  considered  starboard  or 
port  with  reference  to  the  entrance  to  any  port  from  sea- 
ward. 

Entrance  to.  The  entrances  of  channels  or  turning-points  are  marked 
by  conical  buoys  with  or  without  staff  and  globe  or  triangle, 
cage,  &c.  Singled-colored  can-buoys,  either  black  or  red, 
mark  the  starboard  side,  and  buoys  of  the  same  shape  and 
color,  either  checkered  or  vertically  striped  with  white,  mark 
the  port  side  $  further  distinctions  are  given  when  required, 
by  the  use  of  conical  buoys  with  or  without  staff  and  globe, 
or  cage,  globes  being  on  the  starboard  and  cages  on  the 
port  hand. 

Middle  ground.  Where  a  middle  ground  exists  in  a  channel  each  end  of  it 
is  marked  by  a  buoy  of  the  color  in  use  in  that  channel,  but 
with  annular  bands  of  white  and  with  or  without  staff  and 
diamond  or  triangle,  as  may  be  desirable  ;  in  case  of  its  be- 
ing of  such  extent  as  to  require  intermediate  buoys,  they  are 
colored  &s  if  on  the  sides  of  a  channel.  When  required,  the 
outer  buoy  is  marked  by  a  staff  and  diamond,  and  the  inner 
one  by  a  staff  and  triangle. 

wrecks.  Wrecks  are  marked  by  green  nun-buoys. 

Marks.  Each  buoy  is  plainly  marked  with  a  running  number  and 

the  name  of  the  locality  where  it  belongs. 

The  white  stripes  or  checkers  of  buoys  are  about  20  per 
cent,  less  in  size  than  the  black  and  red,  it  being  found  that 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  97 

the  characteristic,  distinctions  of  the  buoys  are  better  ob- 
served at  a  distance  by  this  inequality. 

Bell-buoys,  of  which  there  are  many  in  use,  are  constructed    Beii-buoys. 
of  iron,  and  have  four  hammers  or  clappers,  each  hung  by 
a  Y,  which  prevents  jamming  and  obviates  the  use  of  guides. 
They  cost  about  £200  ($1,000)  each. 

At  Blackwall  the  buoys  are  kept  under  a  commodious    Buoy-shea. 
buoy-shed,  with  convenient  arrangements  of  rails,  &c.,  for 
moving  them.     The  sinkers  are  square  and  of  iron.     The 
prices  of  iron  buoys  most  recently  obtained  are  as  follows  :    Pricesofbuoys. 

Eight-foot  drum-buoy,  price  £32  10s.,  ($162.50.) 

Eight-foot  spherical  buoy,  price  £145,  ($725.) 

Eight-foot  water-ballasting  buoy,  price  £82  10s.,  ($412.50.) 

Thirteen-foot  water-ballasting  buoy,  price  £198  6s.  8d., 
($991.66.) 

Bell-buoy,  price  £224  12s.,  ($1,123.) 

At  the  depot  are  two  towers,  each  having  a  fixed  lens  of   Towers    in 

which   tests  are 

the  second  order,  and  in  them  are  tested,  under  the  direction  made. 
of  Professor  Tyndall  or  Mr.  Douglass,  the  diiferent  lamps, 
lenses,  and  oils,  the  effect  of  fog,  &c. 

The  principal  point  of  observation  is  Greenwich,  distant 
about  two  miles. 

There  are  several  light-house  depots  on  the  coast  of  En-de^jt|h^nbo^ 
gland,  at  Yarmouth,  Coquet  Island,  an cj  other  places,  but  coastofEu»laud- 
Blackwall  is  the  principal  depot  for  manufacture,  supply, 
and  repair. 

The  immediate  agents  through  which  the  authority  ofei^1P>|rijj5^; 
Trinity  House  is  exercised  are  called  superintendents,  and  House  Districts. 
each  has  some  special  duties  assigned  him,  either  the  sole 
care  of  the  service  in  some  specified  part  of  the  coast  or  the 
charge  of  some  special  branch,  such  as  the  supply  and  store 
houses  at  Blackwall.    The  tenders  are  under  their  orders,  orders^?  suife* 
They  wear  a  uniform  on  all  occasions  when  on  duty. 

Light-keepers   are   appointed  by  the   corporation.     The    Keepers. 
rules  require  that  applicants  shall  be  between  the  ages  of  19 
and  28.     They  must  produce  certificates  of  character  arid 
physical   ability,  and  (from  a  schoolmaster)  of  ability  to 
read,  write,  and  perform  simple  operations  of  arithmetic. 
As  vacancies  occur  successful  applicants  are  taken  on  pro-ries.up 
bation,  i.  <?.,  are  appointed  supernumerary  light-keepers. 

They  are  then  sent  to  the  depot  at  Blackwall  and  placed    Instructioll  to 
under  the  orders  of  tlie  superintendent  there.    They 
carefully  trained  in  the  use  and  care  of  lamps  and  all  light- 
house  apparatus,  including  meteorological  instruments  5  the 
keeping  of  the  light-house  journal  and  accounts,   and  the 
general  management  of  affairs  at  a  light-house. 
S.  Ex.  54 7 


98  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

certificates     A  certificate  of  the  lowest  grade  is  given  for  competency 

given.  .        ,     .      ,     . . 

in  their  duties. 

A  second  course  of  instruction  includes  the  use  of  tools  in 
carpentry  and  plumbing,  that  he  may  be  able  to  effect 
ordinary  repairs  ;  also  the  management  and  general  knowl- 
edge of  the  steam-engine. 

A  third  course  includes  instruction  in  the  management  of 
the  magneto-electric  machine  and  lamp. 

A  fourth  course  includes  the  use  and  management  of  fog- 
horn apparatus. 

Separate  certificates  are  given  for  each  course. 

^nere  are  alway  s  ci  ght  of  these  candidates  for  light-keepers 
and  at  Blackwall,  and  two  at  South  Foreland,  the  latter  for  in- 

South  Foreland. 

struction  in  the  management  of  electric  lights,  and  to  the 
great  care  exercised  in  their  selection,  and  the  thorough- 
ness with  which  they  are  instructed  before  they  enter  upon 
their  duties  as  keepers,  is  to  be  attributed  the  excellent 
condition  of  the  lights,  towers,  dwellings,  and  grounds  that 
I  observed  at  every  station  which  I  afterward  visited. 
Supernumera-     Supernumeraries  are  supplied  with  uniforms,  and   are 
and  paidnif°?med  paid  at  the  rate  of  £45  ($225)  per  annum ;  but  on  obtaining 
the  four  certificates  and  giving  satisfactory  proofs  of  steadi- 
ness and  sobriety,  they  become  entitled  to  an  assistant 
keeper's  pay. 
The  rates  of  pay  are  as  follows : 


Grade  of  keeper. 

<D    . 

s-t  a 

p 

II 

§2 

Is 
p 

Principals  who  have  served  as  such  above  10  years  if  insured 

£    s. 
72    0 

£  s 
3    0 

Principals  who  have  served  as  such  above  10  years,  if  uninsured  

70  10 
63    0 

0    0 
3    0 

Principals  above  5  and  under  10  years  if  uninsured         

66  10 

0    0 

66    0 

3    0 

Principals  under  5  years  if  uninsured 

64  10 

0    0 

Assistant  keepers  who  have  served  as  such  above  10  years,  if  insured.  . 
Assistant  keepers  who  have  served  as  such  above  10  years,  if  uninsured 
Assistant  keepers  above  5  and  under  10  years  if  insured     

58    0 
56  10 
56    0 

3    0 
0    0 
3    0 

54  10 

0    0 

54     0 

3    0 

Assistant  keepers  under  5  years  if  uninsured           

52  10 

0    0 

g.  Keepers  pen-  When  no  longer  able  to  do  service,  keepers  are  pensioned, 
the  pension  computed  on  an  estimated  allowance  of  £18,  in 
addition  to  the  above  scale. 

Term  of  service     Keepers  and  assistants  at  rock  and  screw-pile  stations 
screw-pile     sta-  remain  on  shore,  in  rotation,  one  month  each. 

The  regulations  in  regard  to  the  care  of  lamps  and  prem- 
ises and  keeping  watch  are  much  the  same  as  our  own,  but 
where  mineral-oil  is  used,  the  following  instructions  are 
added : 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  99 

u  The  oil  is  to  be  placed  iD  the  metallic  cisterns  provided  careofmmerai- 
for  the  purpose  ;  and  these  are  to  be  kept  perfectly  closed  01 
by  means  of  the  cover  and  tops  with  which  they  are  pro- 
vided. In  drawing  oil  from  the  cisterns  it  is  to  be  drawn 
into  a  proper  can,  provided  with  an  oil-tight  screwed  cover 
and  au  air-tight  screwed  cap  to  the  spout.  After  charging 
the  lamps  the  can  is  to  be  returned  to  the  store  with  the 
covers,  spout,  and  top  screwed  tight.  All  oil  required  for 
the  service  of  the  establishment  is  to  be  taken  from  the 
store  during  day-light,  and  keepers  are  not,  under  any 
circumstances,  to  enter  the  oil-room  with  a  lighted  lamp  or 
candle." 

IRON    LIGHT  -HOUSES    OFF   THE    MOUTH    OF   THE    THAMES. 

After  leaving  Blackwall  we  proceeded  down  the  Thames  ^fg™jse  iu  tho 
in  the  Trinity  House  steam-yacht  Vestal  on  a  cruise  of 
inspection  of  the  lights  on  the  east  coast  of  England,  during 
which  we  visited  nearly  all  of  them  between  the  Thames 
and  the  Scottish  border.  On  this  journey  it  was  my  good 
fortune  to  accompany  Admiral  (Jollinson,  0.  B.,  and  Cap- 
tain Weller,  of  the  Elder  Brethren,  and  I  shall  long  remember 
the  great  kindness  and  attention  of  which  I  was  the  recip- 
ient from  both  of  these  gentlemen. 

We  passed  the  Mucking  light-house,  situated  in  the  h  Mucking  light- 
Thames,  below  Gravesend,  and  the  Maplin  Sand  light-house, 
off  the  mouth  of  that  river.  Both  of  these  are  screw-pile  lighthouse. 
structures  ;  the  latter  was,  I  believe,  the  second  of  that  kind  H^t  house  S'the 
in  the  world,  having  been  lighted  in  1841,  and  was  one 
the  earliest  applications  of  that  useful  invention  of  Mitchell, 
of  which  we  have  many  examples,  there  being  more  than  Number  of 
fifty  light-houses  built  on  that  plan  in  the  United  States,  houses1"  in  1Sthe 

It  may  be  mentioned  here  that  the  first  screw-pile  light- 


Maplin      Sand 
hous 


house  was  built  at  the  mouth  of  the  river  Wyre,  on  thelighWlonsebuilt- 
northwest  coast  of  England,  two^or  three  years  before  the 
light-house  on  the  Maplin  Sand.  The  screws  were  three 
feet  in  diameter,  the  piles  five  inches  ;  and  above  the  ground, 
instead  of  iron,  as  at  Maplin,  wooden  columns  were  used. 
This  light-  house  was  destroyed  in  1870.  st™"  ed  n  de" 

The  Maplin  Sand  light-house,  a  view  of  which  is  shown    Description  of 
in  Plate  Y,  is  a  hexagonal  structure,  with  one  central  and 
eight  exterior  piles.    The  piles  were  driven  vertically,  but 
above  the  water-line  they  bend  toward  the.  center  and  in- 
cline in  a  pyramidal  form  to  the  lantern-floor.    The  screws    screws. 
are  four  feet  in  diameter,  the  piles  five*'  inches,  and  they 
support  cast-iron  columns  12  inches  iu  diameter.    The  col-  columns. 


100  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

umns  are  very  strongly  braced,  and  the  structure  had  an 

appearance  of  great  strength. 
Gnnfleet  light-     We  stopped  .  at  the  Gunfleet  light-house,  situated  on  a 

sand  of  that  name,  north  of  the  mouth  of  the  Thames,  and 

thirty-one  miles  from  the  Nore  light-ship.     It  is  exposed  to 

the  full  force  of  the  Korth  Sea. 
Plies.  There  are  one  central  and  six  exterior  piles  supporting 

columns  of  about  12  inches  in  diameter,  strongly  braced. 
sockets.  The  sockets  for  the  columns  are  not  cast  in  one  with  the 

sockets  for  the  braces,  but  the  latter  are  bolted  against  the 

face  of  the  piles  by  tap-bolts. 
Form  of   the     Unlike  Maplin  Sand  light  house,  the >  piles  were  not  driven 

structure. 

vertically,  and  are  inclined  from  the  bottom  to  the  top  in 

the  form  of  a  pyramid.     The  piles,  braces,  and  sockets  are 

of  a  very  massive  character,  and  give  an  appearance  of 

great  durability  and  of  the  strength  which  the  site  demands. 

^Keepers' dwell-     rpne  Dwelling  for  the  keepers  (below  the  lantern-floor)  is 

but  one  story  in  height,  and  is  smaller  and  less  convenient 

than  in  similar  structures  in  the  United  States.     The  sides 

and  roof  are  made  of  corrugated  iron  with  wrought-iron 

Additionaiail<yie_piates.     Below  the  floor  of  the  dwelling  additional 

space  furnished.         & 

space  is  furnished  by  placing  a  store-room  in  an  inverted 

pyramid,  to  which  access  is  had  by  a  ladder  from  the  gallery. 

The  dwelling  is  divided  into  a  living  room,  (also  used  as  a 

Reason  ibr  the  kitchen,)  a  bed-room,  and  an  oil-room.     It  was  stated  that 

thTs™ucture.m°  the  sea  rarely  rises  to  the  bottom  of  the  house,  and  the  ob- 
ject of  the  peculiar  form  given  was  to  allow  the  wind  and 
spray  to  be  warded  off  without  imparting  shocks  to  the 
structure.  I  should  judge  the  device  to  be  one  of  question- 
able utility,  and  that  but  little  more  expense  would  have 
been  incurred  by  raising  the  building  a  few  feet  higher  and 
placing  another  full  story  for  the  accommodation  of  the 
keepers. 

Keepers.  There  are  two  keepers,  one  less  than  we  would  have  in 

the  United  States,  and  it  will  be  observed  throughout  this 
report  that  the  British  lights  are  maintained  by  a  less  num- 
ber of  keepers  for  each  than  for  the  same  order  of  light  in 
our  service. 
catoptric    ap-     The  lantern,  which  is  large  and  commodious,  contains  a 

paiatus         m-  revojving  catOptric  apparatus  composed  of  fifteen  reflectors 

and  Argand  burners  in  sets  of  five,  placed  on  a  frame  of 

Red  light,  how  three  sides,  and  this  being  a  red  light,  panes  of  red  glass,  in 

managed.  frames  hung  on  hinges,  were  placed  in  front  of  each  reflector. 

This  structure  seems  admirably  adapted  to  the  locality,  and 
1  should  think  the  question  of  replacing  by  similar  struc- 
s! tures  some  of  the  great  number  of  light-ships  which  mark 


Plate  V. 


^s 

I 

.  ^ 


'    '" 

•    •'". 

MAPLIN     SAND     LIGHT-HOUSE. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  101 

the  channels  through  the  shoals  obstructing  navigation  on 
the  east  coast  of  England,  would  have  attracted  attention, 
and  there  are  probably  some  special  reasons  why  it  has  not 
been  done. 

While  the  first  cost  of  a  screw-pile  light-house  in  an  ex-    comparative 
posed  locality  is  greater  than  that  of  a  light-ship,  the  cost  flight  -Sis 
of  maintenance  as  well  as  of  repairs  is  much  less ;  and  be- aml 
sides,  the  danger  which  sometimes  occurs  of  light-ships 
being  dragged  from  their  stations  and  leading  vessels  into 
the  very  dangers  from  which  they  are  intended  to  warn 
them,  is  avoided. 

These  considerations  have  induced  us  to  replace  our 
light-ships  by  screw-pile  light-houses  except  in  the  case  of 
shifting  shoals  like  those  off  the  island  of  Nantucket. 

ORFORDNESS. 

We  did  not  visit  these  light  houses,  but  as  viewed  from 
seaward  they  are  substantial  structures.     Seen  in  one,  in 
either  direction,  they  guide  clear  of  certain  dangers ;  and  H^Sfhouses  *at 
besides  this,  they  mark  out,  by  means  of  red  sectors  of  light,  Orfordness- 
other  dangers.     This   was  the  first  instance  I  saw  of  what    "Redcuts-" 
the  Elder  Brethren  call  "  red  cuts,"  which  I  shall  fully  de- 
scribe when  I  come  to  treat  of  the  lights  at  Souter  Point  and 
Coquet  Island.     We  ran  from  the  white  into  the  red  light, 
and  the  line  of  division  was  quite  distinct. 

YARMOUTH. 

On  the  12th  of  June  we  arrived  at  Yarmouth,  where  there  r>epot  at  Yar- 
is  an  extensive  supply  and  buoy  depot  on  the  river  Yare. 
It  consists  of  a  very  fine  buoy  store-house,  a  store-house  for 
chain-cables,  a  cooper-shop  for  wooden  buoys,  smith  and 
paint  shops,  a  store-house  for  oil,  slips  for  the  repair  of  light- 
ships, and  quarters  for  the  superintendent,  foremen,  and 
clerks.  There  is  also  a  fire-proof  store-house  for  the  signal- 
rockets  used  on  the  light-ships. 

The  buoy  store-house  is  well  built  of  masonry,  paved  with  Buoy  store- 
wooden  blocks,  and  traversed  by  a  railway.  A  trussed 
traveling-crane,  of  excellent  construction,  supported  on 
girders  resting  on  piers  projecting  from  the  side-walls,  gives 
great  facility  for  moving  the  buoys ;  large  sliding-doors 
open  toward  the  river,  and  on  the  wharf  is  placed  a  ten-ton 
crane  for  hoisting  the  buoys  into  the  steam-yacht,  Beacon, 

Yacht  Beacon. 

which,  with  its  steam-launch  or  pinnace,  is  constantly  en- 
gaged in  the  service  of  the  district  under  the  superintend- 
ence of  Mr.  Emerson. 


102 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Buoys  repaired.  At  this  depot  are  painted  and  repaired  the  buoys  for  the 
neighboring  coast  and  channels,  and  a  large  number  are 
kept  in  store  for  relief  and  to  supply  losses. 

brouTte\ibeach     ^oe  wooden  buoys  (not  spar-buoys ;  of  these  I  believe  the 

year.  English  have  none)  are  brought  in  once  a  year  for  painting, 

iron  buoy s but  the  iron  buoys  are  painted  without  being  unshackled 

painted  at  their 

moorings.          from  their  moorings,  and  are  but  rarelv  ch  an  fired.     The 


Marking 
buoys. 


depot™       1 


5,)   provided 

Fig.  5. 


with 


from  their  moorings,  and  are  but  rarely  changed. 
of  buoys  are  marked  with  their  numbers  and  names;  these 
last  being  the  names  of  the  spits,  channels,  &c.,  which  they 
are  intended  to  point  out.  A  practice  very  different  from  our 
own  is  that  of  painting  these  numbers  and  names  on 
heavy  canvas  strips  of  two  thicknesses,  which  are  fastened 
to  the  buoys  by  means  of  bolts  and  nuts,  or  by  lashings. 
These  strips  are  frequently  changed,  (without  lifting  the 
buoys,)  as  it  is  considered  of  great  importance  that  the 
names  and  numbers  of  the  buoys  shall  always  be  plain  and 
distinct. 

Method  of  deter-     There  are  a  great  many  buoys  and  several  light-ships 
-  ships  in  view  from  the  high  lookout-  tower  above  the  dwelling  of 
1   in  the  superintendent,  and  Mr.  Emerson  has  contrived  a  simple 
and  ingenious  mode  of  detecting  if  any  of  them  have  been 
driven  from  their  positions. 

A  large  telescope,  (shown  in  Fig. 
spider-lines,  is  movable  on 
a  vertical  axis,  c,  fixed  upon 
a  platform  on  which  are 
marked  cross-lines  c  a,  c  a, 
c  a,  and  the  names  of  the 
buoys  and  light-  ships,  which 
indicate  the  precise  direc- 
tion in  which  they  should  be 
found  by  means  of  a  pointer, 
c  &,  attached  to  the  pedestal 
of  the  telescope;  thus  the 
slightest  drifting  from  their 

proper  positions  is  at  once  "  Buoy-finder.  ~ 

discovered. 

In  regard  to  buoys,  I  should  mention  that  the  buoy-list 
of  the  English  differs  in  several  respects  from  our  own. 
There  is  noted  in  regard  to  each  buoy  its  name,  size,  descrip- 
tion, (kind,)  color,  material,  weight  of  sinker,  fathoms  of  chain, 
depth  of  water,  when  first  laid,  and  date  of  last  removal. 

The  following  is  an  example  : 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


103 


Remarks. 

Color  altered  from  white,  1859. 
Name  and  color  altered,  1869. 
Color  altered,  1869. 
Color  altered,  18G9. 

1 

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i 

c 

^ 

§ 

Q 

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inn 

d 

fl 

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2Srt  JH°° 

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-VM.  JO  lUdad 

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grH               rHrt 

2                ^ 

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ri 

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j|      U93[ins 

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1 
5 

i    llsii 

££&££ 

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g 

§ 

Black  

Black  and  white  checkered  .  . 
Red  and  white  striped  
Red  and  white  checkered  .  .  . 
Red  and  white  striped  

(description)  of  buoys  :  H.  B. 

. 

ts 

o 

:w  :'  : 

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<o 

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1 

i&i* 

ooouo 

73 
fcfl 

•9ZJS 

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£ft 

w  .- 

-§      i 

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Is 

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pi 

1 

West 
Dike  
Quern  

Checkered  Fairway  .  .  . 

S-ia 

1j 
|| 

5« 
SH 

If 

104 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


A  spare  light- ship  is  kept  at  Yarmouth  depot,  and  I  saw 
one  repairing  in  the  dock.  The  bottom  was  exposed,  and 
was  provided  with  bilge-pieces  or  "  bilge-keels  "  to  prevent 
rolling,  as  shown  in  Fig.  G. 

Fig.  6. 


Position. 


Bilge-keels  for  Light-ships. 

1  was  informed  that  this  was  the  common  practice  in  the 
English  service. 

HAlSBOROUaH. 

There  are  two  first-order  sea-coast  fixed  lights  at  Hais- 
borough,  in  the  county  of  Norfolk,  the  northern  or  high 
light  being  140  feet,  the  southern  or  low  light  94  feet,  above 
the  sea.  They  are  about  a  mile  apart  and  form  a  range  or 
lead  for  vessels  passing  through  Haisborough  Gat. 
Competitive  At  the  time  of  my  visit  to  this  station  there  had  been  in 

trial  of  gas  and  „  .  ,. ..          ,    .    , 

Douglass^  four- progress  for  some  months  an  important  competitive  trial 

*mp~     between  a  Douglass  four-wick  lamp  in  the  low  tower  and  a 

gas-lamp,  patented  by  Mr.  Wigham,  of  Dublin,  in  the  high 

tower.    The  apparatus  for  the  latter  was  manufactured  by 

Edmundson  &  Co.,  engineers,  of  London  and  Dublin. 

The  commissioners  of  Irish  lights  have  introduced  the 
use  of  gas  into  several  of  their  light-houses,  as  we  were  in- 
formed by  Professor  Tyndall  when  he  was  in  the  United 
States  last  year,  and  in  the  remarks  which  he  made  at  a 
of  session  of  the  Philosophical  Society  of  Washington,  he 
mentioned  the  great  "  flexibility  "  of  this  kind  of  light  when 
used  for  light-house  illumination. 

I  will  treat  more  particularly  of  this  invention  of  Mr. 
Wigham  when  I  describe  the  Irish  lights  that  I  visited  with 
him,  but  I  will  state  here  that  1  found  the  lamp  to  consist 
of  a  horizontal  circular  disk  (hollow)  about  one  foot  in 
diameter,  supported  upon  a  stand  and  into  which  the  tubes 


Gas  in  use  in 
Irish  light- 
Louses. 


Flexibility 
gas-light. 


Lamp. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  105 

supplying  the  burners,  in  sets  or  frames,  were  connected  by 
joints  made  tight  by  means  of  quicksilver. 

The  lamp  is  designed  to  burn  28  jets  in  clear  weather.    Arrangement 
They  are  arranged  in  concentric  rings,  the  diameter  of° 
the  inner  row  being  about  the  same  as  that  of  the  outer 
burner  of  the  ordinary  four- wick  lamp,  i.  <?.,  four  inches. 

In  case  the  atmosphere  becomes  hazy,  an  additional  exte-    increase  of 
rior  row  of  20  jets  is  placed  in  two  frames  of  180°  each, nv 
each  frame  being  supported  by  a  short  supply-tube  set  into 
a  cup  containing  a  quicksilver  joint. 

During  this  operation  the  lights  from  the  28  jets  forming 
the  nucleus  are  turned  low,  and  when  the  cocks  are  re- 
opened the  flame  from  these  lights  the  exterior  row. 
As  required  by  increasing  density  of  fogs  or  thick  weather, 
additional  rows  of  jets  are  successively  placed  in  each  case, 
increasing  the  number  by  20,  so  that  from  28,  the  number 
in  the  nucleus,  the  various  powers  are  48,  68,  88,  and  108 
jets,  the  latter  being  used  only  in  very  thick  weather  or 
dense  fog. 

There  is  no  chimney  surrounding  the  flame,  but  above  it,    ciiimney  o, 
at  a  distance  of  about  12  inches,  is  suspended  a  chimney  of mica- 
mica,  into  which  the  flame  is  carried  by  the  draught  through 
the  cowl  of  the  lantern.    The  mica  chimneys  vary  in  diam- 
eter, and  are  changed  to  accord  with  the  number  of  jets 
used. 

The  entire  operation  of  changing  from  one  set  of  jets  to    Tirae  OCCUpieA 
the  next  higher  or  lower,  or  from  the  lowest  to  the  highest,  JjJfiJJgJt81*0*" 
or  the  reverse,  and  also  changing  the  mica  chimneys,  occu- 
pies but  a  few  seconds,  not  more  time,  I  should  think,  than 
the  trimming  of  a  four-wick  lamp. 

The  diameter  of  the  flames  corresponding  to  the  different    Diameters    of 
powers  of  the  lamp  are  respectively  3f,  5J,  7J,  9J,  and  10£ tho  flaraes' 
inches  for  the  28,  48,  G8,  88,  and  108  jets.     It  will  therefore 
be  observed  that  a,  great  part  of  the  larger  flames  is  neces- 
sarily exfocal,  increasing  the  divergence  of  the  light,  and 
the  increase  of  intensity  when  seen  at  any  point  within  the 
arc  of  visibility  is  no  doubt  due  to  the  great  thiclcness  of  the 
flame. 

The  heat  inside  the  lantern,  when  the  larger  flames  are    Heat  produced 
turned  on,  is  very  great,  but  I  was  told  that  it  was  not  8»f-|L»2f    largest 
ficient  to  injure  the  lenticular  apparatus  nor  to  seriously 
aimoy  the  keepers. 

As  in  the  electric  light  at  South  Foreland,  an  oil-lamp  is    ou-iamp  on 

T  .L  i          -i  •       >i  i  i  '  />  hand  in  case  of 

always  at  hand  in  the  watch-room,  and  in  case  ot  accident  accident, 
to  the  gas-lamp,  it  can  be  removed  and  the  former  lighted 
in  less  than  two  minutes.     I  did  not  learn  that  occasion  for 


106  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

its  use  had  yet  occurred,  and  I  should  think  it  even  less 

likely  to  occur  here  than  in  the  case  of  the  electric  light. 
Coal  used.  In  the  gas-house  near  the  tower  common  Newcastle  coals 

are  used  for  heating  the  five  retorts,  and  canuel-coal  yields 

the  supply  of  gas. 
Gas,  bow  con-     The  gas  issuing  from  the  retorts  is,  after  being  caused  to 

ducted  to  the  re- 

ceivers. pass  through  water,  conducted  through  several  layers  of 

slaked  lime  contained  in  flat  boxes,  thence  through  a  sys- 
tem of  pipes,  depositing  the  tar-product  en  route,  and  finally 
is  carried  into  the  receivers  (of  4,900  cubic  feet  capacity) 
from  which  the  light-house  lamps  are  supplied. 

Meters.  Separate  meters  are  used  for  registering  the  quantities  of 

gas  consumed  in  the  dwellings  and  in  the  light-house,  and 
con-  each  amount  is  reported  monthly  to  the  Trinity  House.    The 


s'  consumption  of  gas  in  the  48-jet  burner,  in  a  night  of  7J 
hours,  was  830  feet,  or  2.3  feet  per  burner  per  hour. 

Consumption     In  the  months  of  April  and  May  preceding  my  visit  the 
Say,  iB73.      "  consumption  of  gas  in  the  tower  had  been  21,980  and  26,450 
feet  respectively. 

Number  of  There  are  two  keepers  at  each  light-house  at  Haisborough, 
(that  being  the  rule  for  all  English  sea-coast  lights,  except 

Laborer  em-  rock-stations,)  and  in  addition  to  them  is  employed  a  laborer 
from  the  neighboring  village,  to  make  the  gas,  but  his 
attendance  at  the  station  is  only  required  every  other  day. 
He  is  paid  a  weekly  salary  of  fifteen  shillings,  (about  $3:75.) 

Fuel  saved  by  ^  large  saving  in  fuel  is  effected  by  consuming  the  tar 
which  is  produced  in  the  manufacture  of  the  gas. 

A  general  plan  of  the  buildings  at  the  light-house  is 
shown  in  Plate  VI. 

Plan  of  tower.  The  tower  is  built  of  brick  and  stuccoed  ;  it  and  the  dwell- 
ings, out-buildings,  and  walls  surrounding  the  premises  are 
kept  scrupulously  clean  and  neat. 

stairs.  The  interior  of  the  tower  is  cylindrical  ;  the  stairs,  like 

those  in  the  towers  at  South  Foreland,  are  circular,  and 
apparently  self-supporting,  one  end  only  being  built  into 
the  wall,  as  in  our  Treasury  at  Washington,  and  in  several 
other  buildings  I  have  seen  in  America.  This  method  of 
stair-building  I  found  to  be  universal  in  Europe,  in  private 

comparison  of  as  well  as  public  buildings.  I  think  our  most  recent  towers 
tor?,  with  conical  interior  and  iron  stairs  winding  around  the 
interior  of  the  cone,  superior  to  any  I  saw  in  Europe. 
European  towers  are,  however,  superior  to  any  constructed 
by  us  until  within  a  few  years,  on  account  of  the  greater 
amount  of  light  and  the  airiness  of  towers  with  a  free  and 
open  interior. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  107 

The  practice  abroad  is,  in  most  cases,  to  make  the  interior 
wall  cylindrical  and  the  exterior  one  conical,  leaving1  an  un- 
necessarily large  air-space  between  the  two  near  the  base, 
while  in  our  latest  towers,  such  as  those  at  Bodie's  Island, 
Saint  Augustine,  and  others,  a  small  air-space  sufficiently 
large  for  the  purpose  intended  is  left  between  the  walls, 
(both  of  which  are  conical,)  and  the  space  gained  by  this 
mode  of  construction  is  thrown  into  the  interior. 

The  amount  of  masonry  in  our  present  system  is  the  same    Masonry  in  old 
as  in  the  former,  and  is  calculated  to  resist  by  its  weight  SJS 


the  overturning  effect  of  the  severest  gales. 

At  Haisborough  the  oil-cellars  are  placed  below  the  floor    Oil-c 
of  the  towers,  the  cisterns  or  cans,  each  holding  about  100 
gallons,  being  arranged  around  the  walls.    There  are  no 
arrangements  for  pumping  the  oil  to  the  top  of  the  towers, 
and  it  is  carried  by  the  keepers  by  hand.    The  filling-room    Measures     to 
below  the  lantern  is  provided  with  brass  measures  of  differ- 
ent  sizes,  from  a  gallon  downward,  and  every  morning  the 
keeper  notes  the  consumption  of  oil  the  previous  night,  and 
makes  monthly  returns  of  the  amounts  to  the  Trinity  House. 

These  measuring-  vessels,  the  brass-work  of  the  lamp,  and 
the  hand-rails  of  the  stairs,  are  always  neatly  burnished. 

The  English  lanterns  in  all  the  recent  light-houses  have  ba?8i.agonal  8ash" 
diagonal  sash-bars,  as  it  is  considered  that  the  upright  bars 
obstruct  a  large  portion  of  the  light  in  certain  directions. 
I  will  more  fully  treat  of  the  latest  lanterns  which  I  saw, 
and  particularly  of  the  advantages  of  the  diagonal  sash-bars, 
when  I  come  to  describe  the  light-house  at  Holyhead. 

The  glass  for  the  lanterns  at  Haisborough  is  half  an  inch    Glass  for  ian- 
thick,  the  panes  are  lozenge-shaped,  and  the  surfaces  are  te 
curved  to  conform  to  the  diameter  of  the  lantern. 

No  special  means  are  used  to  prevent  large  sea-fowl  from 
breaking  the  lantern-glass,  and  I  was  told  that  the  necessity 
of  such  means  does  not  exist  in  England  as  it  does  with  us, 
particularly  on  our  southern  coast. 

In  the  Ian  tern  -floor  there  is  provided  a  basin,  covered    Basin  in  ian- 
when  not  in  use,  into  which  is  led  rain-water  from  the  roof  tern~floor* 
for  use  in  washing  the  interior  of  the  lantern. 

The  air,  which  supports  the  combustion  of  the  lamp,  is  Egress  of  air. 
not  let  directly  through  the  sides  of  the  lantern,  as  in  our 
service,  but  is  admitted  below  and  passes  through  the  grat- 
ing which  forms  the  lantern-floor.  The  object  in  this  is  to 
give  the  air  a  uniform  temperature,  and  great  importance  is 
attached  to  this  in  the  English  service.  (See  Plate  VII.) 

The  windows  of  the  tower  are  arranged  without  admit-    Method  of  veu- 
ting  the  rain,  according  to  an  excellent  plan  which  is  shown  tilation- 


'  108  EUROPEAN   LIGHT-HOUSB    SYSTEMS. 

in  Plate  VIII,  in  which  it  will. be^observed  that  the  upper 
sash  is  hinged  afc  a-,  and  savings,  as  shown  by  the  dotted  arc. 
To  the  lower  part  of  the  sash  is-  fastened  a  rod,  b,  which 
passes  through  a  sleeve,  c,  whicti  is  movable  about  an  axis, 
and  through  which  a  set  screw  passes  by  which  the  window 
can  be  fastened  atr  any  desired  angle.  One  only  of  the 
lower  sashes  opens,  as  is  shown  in  the  -plate. 

cost  of  chang-  The  costof  changing  from  oil  to  gas  at  Haisborough  was 
£51  light.  c  °  about  £1,700,  ($8,500,)  the  gas-holder  and  other  parts  of 
the  apparatus  being  designed  to  serve  both  lights. 

Painting    the     in  the  English  service  the  towers  and  dwellings  are  gen- 

dwellings,      &c., 

periodically.  erally  painted  white  (to  make  them  serve  better  as  day- 
marks)  once  in  four  years,  by  painters  permanently  em- 
ployed by  the  Trinity  House,  and  who  for  this  purpose  visit 
the  stations  in  rotation. 

The  lantern,  watch-room,  &c.,  are  painted  by  the  keepers 

on'ce  a  year.    The  hand-rails,  when  of  iron,  are  painted  with 

bronze  paint,  and  when  they  are  of  brass,  which  is  often  the 

case,  they  are  kept  neatly  burnished. 

wind-vanes     At  the  summit  of  the  lanterns  are  always  placed  wind- 

and       lightning-  IT    i  ,     • 

rods.  vanes  and  lightning-rods. 

Flag-staffs.          Flag-staffs  are  provided  at  each  station,  placed  either  on 
the  tower  or  in  the  grounds  surrounding  it.     The  Trinity- 
House  flag  is  displayed  whenever  the  tenders  are  seen  ap- 
proaching; also  on  Sundays  and  holidays.     I  observed  that    . 
a  neat  pavement  of  pebbles,'  about  15  inches   wide,  was.  -- 
laid  at  the  foot  of  each  wall,  to  protect  the  soil  from  the 
wash  from  the  wall  in  rainy  weather. 

Rooms  fur-     In  regard  to  the  dwellings,  each  keeper  is  furnished  with 
^  keepers.    a  ijving.room?  three  bed-rooms,  a  scullery,  wash-room,  a 
place  for  coals,  and  a  garden. 

Books  at  the  There  are  at  Haisborough,  as  at  all  other  light-stations 
in  the  English  service,  certain  books  furnished  by  the 
Trinity  House  in  which  are  kept  the  records  of  the  stations. 
Among  them  I  observed  an  Order- Book,  in  which  any 
officer  of  the  corporation  enters  the  orders  or  directions 
given  by  him  to  the  keeper  while  on  his  visit  to  the  station. 
It  is  his  duty  to  observe  whether  previous  orders  of  himself 
or  others  have  been  properly  executed. 

Another  book  is  called  the  Visitors'  Book,  and  in  it  are 
recorded  the  names  and  professions  of  the  persons  visiting 
the  station. 

Libraries.  Small  libraries  are  provided  at  each  station  for  the  use  of 

the  keepers  and  their  families.  They  always  include  a 
Bible  and  Prayer-book,  and  are^therwise  composed  of  books 
suitable  for  persons  of  their  class. 


IS-T ORDER  ENGLISH  LIGHTHOUSE. 

UPPER  PART  OF  TOWER. 


PLATE  VII- 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  109 

These  libraries  are  interchanged  between  the  stations  on 
the  annual  visits  of  the  supply-vessels. 

Medicine-chests  also  are  furnished  to  each  station.  Medicine-chests. 

I  did  not  observe  any  room  set  apart  especially  for  a  work-    NO  work-rooms 

.  ..  „         .    ,       ,  at    English    stn- 

shop  as  at  our  large  stations,  though  keepers  are  furnished  tions. 
with  necessary  tools,  and  their  education  at  Blackwall  in 
mechanical  operations  would,  with  the  general  intelligence 
possessed  by  the  keepers,  make  this  provision  more  useful 
even  than  in  our  own  service. 

A  certain  amount  of  standing  furniture  is  provided  in    Furniture. 
each  dwelling.    It  includes  iron  bedsteads,  chairs,  tables,  a 
desk,  &c. 

When  a  keeper  is  removed  from  one  station  to  another 
(either  to  a  better  one  as  a  reward  of  merit,  or  to  an  inferior 
one  as  a  punishment)  his  family  is  transported  at  public 
expense. 

The  keepers  at  Haisborough,  as  at  all  the  other  stations    uniform  wom 
which  I  visited,  wore  the  neat  uniform  of  the  Corporation  of  y 
Trinity  House. 

From  Haisborough  we  steamed  out  to  the  Xewarp  ^to^- 
ship,  (to  be  noticed  farther  on,)  and  returned  after  dark  to 
observe  from  the  sea  the  comparative  intensities  of  the  gas 
and  oil  lights. 

The  gas-light  is  in  the  northern  light-house,  the  oil-light 
in  the  southern,  on  a  point  of  land  nearer  the  sea,  at  an  ele- 
vation 46  feet  below  the  former,  the  respective  heights  of 
focal  planes  being,  as  before  stated,  140  and  94  feet  above 
the  sea.  The  lower  tower  is  lighted  by  one  of  Douglass's 
four- wick  lamps. 

The  Vestal  was  stopped  at  a  distance  of  six  and  a  half 
miles  from  the  lights,  and  at  a  point  equidistant  from  both. 
The  night  was  clear,  and  the  opportunity  for  fair-weather 
observations  was  excellent.  The  Trinity  House  officers  on 
board  had  directed  the  keeper  of  the  upper  (the  gas)  light- 
house to  burn  the  ordinary  number  of  jets,*viz,  48,  till  9 
o'clock.  At  that  time  the  number  of  jets  wras  to  be  reduced 
to  28,  and  the  changes  were  to  be  as  follows : 

At  9  p.  m.  reduce  to  28  jets ;  at  9.10  p.  m.  increase  to  48    Memoranda  oi 
jets;  at  9.20  p.  in.  increase  to  68  jets ;  at  9.30  p.  m.  increase ch 
to  88  jets  ;  at  9.40  p.  m.  increase  to  108  jets ;  at  9.50  p.  in. 
reduce  to  28  jets;  at  10  p.  m.  reduce  to  68  jetsj  at  10.10 
p.  m.  reduce  to  48  jets  ;  at  10.20  p.  m.  reduce  to  28  jets  5  at  • 

10.30  p.  m.  increase  to  48  jets. 

The  comparative  brightness  of  the  lights  was  estimated    Manner  of  oi>- 
by  observing  them  with  the  naked  eye,  and  also  through  fights.1  n  fi 
different  thicknesses  of  red  glass.     The  method  of  using 


110  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

the  latter  was  to  place  successive  layers  of  small  plates  of 

glass  into  frames  made  for  the  purpose,  until  one  or  both  of 

thelights  when  seen  through  them  could  barely  be  discerned, 

and  I  found  that  the  eye  could  thus  much  more  readily  detect 

differences  between  the  intensities  of  the  lights  than  when 

viewing  them  without  the  use  of  the  glass  media. 

Question  of     I  am  riot,  however,  satisfied  as  to  the  advisability  of  using 

t fn t e'a n| ituSs red  glass,  since  it  is  probable  that  those  flames  which  have 

chormTf  ar^the  more  of  that  color  in  their  composition  would  be  placed  at  a 

disadvantage,  and  I  would  prefer  a  neutral-tinted  glass. 
Appearance  of  When  we  first  observed  the  lights  from  our  position  the 
gas-light  (48  jets)  was  not  equal  to  the  oil-light ;  between 
9  p.  m.  and  9.10  p.  m.  (28  jets)  it  was  still  more  inferior ; 
between  9.10  and  9.20  (48  jets)  the  same  difference  was  ob- 
served as  before ;  between  9.20  and  9.30  (68  jets)  we  pro- 
nounced the  two  lights  equal. 

Fog  obscures  At  this  time  a  dense  fog  rolled  in  from  seaward,  obscuring 
both  lights,  and  we  steamed  toward  them  till  we  got  within 
(as  we  afterward  found)  two  miles  of  them,  both  continuing 
eclipsed.  About  midnight  the  fog  rolled  away,  and  the 
lower  (oil)  light  came  gradually  into  view,  but  vvhen  it  had 
apparently  attained  its  full  power  we  could  still  see  no  sign 
of  the  upper  (the  gas)  light. 

Fifteen  minutes  afterward  the  upper  light  dimly  ap- 
peared and  slowly  increased  in  brightness  till  about  half 
superiority  of  past  12,  when  both  lights  were  fairly  free  from  the  fog,  and 
hts'     in  the  opinion  of  all  the  party  the  upper  (gas)  was  very 
much  superior  to  the  lower  (oil)  light. 

As  the  time  covered  by  the  instructions  given  to  the 
keepers  had  long  since  expired,  it  was  not  until  our  return 

London  that  we  learned  the  number  of  gas-jets  burning, 
which  was  then  shown  to  be  108,  the  number  corresponding 
to  the  instructions  of  the  keepers  for  times  of  dense  fog. 

It  was  fortunate  for  our  experiment  that  the  fog  shut  in 
during  our  observations.  That  the  oil-light  was  first  to  be 
seen  was  no  doubt  due  to  the  fact  that  the  fog  rolled  in  over 
the  land  from  seaward,  (though  this  was  not  apparent  to  us, 
there  being  no  perceptible  breeze,)  and  that  light,  being  on 
a  point  projecting  into  the  sea,  was  first  free  from  it. 

^s  ^ar  as  determined  by  our  experiments  at  Haisborough, 
ration  of  lights.  I  have  no  doubt  the  following  judgments  were  correct : 

1st.  In  fair  weather  the  gas-light  of  68  jets  was  equal  to 
the  first-order  light  from  the  oil-lamp  of  four  wicks  as  im- 
proved by  Mr.  Douglass. 

2d.  Neither. the  light  of  28  nor  of  48  jets  was  equal,  but 
that  of  108  jets  was  decidedly  superior  to  the  oil-light. 


VENTILATING  WINDOW 

FOR 
LIGHTHOUSE  TOWERS. 


PLATE  VIII. 


SECTION. 


INSIDE  ELEVATION. 


ENLARGED  DETAI  L 
FASTENING. 


& 

r>V 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  Ill 

3d.  In  a  dense  fog,  to  an  observer  at  a  distance  of  two 
miles,  neither  the  gas-light  of  108  jets  nor  the  oil-light  from 
a  four-wick  burner  gives  any  indication,  however  slight,  of 
its  existence. 

It  has  been  observed  by  Professor  Tyndall,  in  his  experi-    A  slight  cloud 

•¥-»    i  I-        11  t        -i    ^n  f°f    steam     snffi- 

ments  m  Dublin,  that  a  steam-cloud  ot  even  a  tew  feet  olcient  to  obscure 
thickness  is  sufficient  to  totally  obscure  the  rays  of  the  sun 
itself,  and  as  either  the  four-wick  oil-lamp  or  the  28-jet  gas- 
light is  sufficiently  powerful  to  illuminate  the  horizon  cor- 
responding to  the  ordinary  elevations  of  sea-coast  light- 
houses, i.  e.,  at  distances  from  eighteen  to  twenty  nautical 
(twenty-one  to  twenty-three  statute)  miles  in  clear  weather, 
it  is  evident  that  the  increased  intensity  of  sea-coast  lights 
is  desired  for  those  intermediate  states  of  the  atmosphere 
between  dense  fog  on  the  one  hand  and  clear  weather  on 
the  other. 

In  these  conditions  of  the  air,  including  all  the  varieties  conditions  of 
of  haziness  and  "  thick"  weather,  up  to  dense  fog,  (and  also 
in  snow-storms,)  light-houses  are  most  useful  ;  for  these  the 
light-house  engineers  of  Europe  are  striving  to  find  the  most siretL 
powerful  lights,  and  to  meet  this  want  the  electric  light 
(which  I  have  described  at  South  Foreland,  and  which  I 
shall  more  clearly  exhibit  in  an  account  of  my  visit  to  the 
light-houses  at  the  mouth  of  the  Seine)  and  the  gas-light 
(such  as  I  have  described  at  Haisborough  and  afterward 
saw  on  the  coast  of  Ireland)  have  been  introduced  within  a 
few  years. 

While  both  these  lights  can  be  maintained  at  moderate    Power  of 
power  in  fair  weather,  they  have  this  advantage  :  they  can  lights  can 

.      *  ,  creased        when 

be  increased  almost  without  limit  when  it  becomes  hazy  needed, 
and  thick  ;  this  can  be  done  without  any  increase  in  the 
size  or  cost  of  the  lenticular  apparatus,  since  the  electric 
light  requires  a  lens  much  smaller  than  that  required  for  an 
oil-lamp,  and  as  I  shall  illustrate  farther  on,  324  jets  can  be 
burned  in  Wigham's  triform  gas-light  without  increasing 
the  size  of  the  lenticular  apparatus  or  the  diameter  of  the 
flame  beyond  the  maximum  (108  jets)  which  I  saw  at  Hais- 
borough. 

It  is  this  power  of  being  increased,  (according  to  the  con-  Flexibility  of 
ditions  of  the  weather,  from  28  jets  by  steps  of  20  at  a  time, 
till  324  jets  the  beam  from  which,  even  when  uncondensed, 
is  equal  to  more  than  the  united  beam  from  6,000  can- 
dles can  throw  their  rays  in  a  solid  beam  through  the 
lenticular  apparatus,)  which  gives  to  the  gas  light  of  Mr. 
Wigham  its  great  "  flexibility,"  to  adopt  the  term  so  hap- 
pily used  by  Professor  Tyndall  when  speaking  of  this  light, 


112  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

and  I  believe  in  this  regard  it  is  superior  to  the  electric 
light, 

*  Economy  muse  In  the  gas-light  in  clear  weather  only  a  sufficient  quantity 
of  gas  is  used  to  carry  the  light  distinctly  to  the  horizon. 
The  large  quantity  required  for  "  thick  "  weather  remains 
stored  in  the  reservoir  till  wanted,  and  the  expensive  light 
is  burned  only  when  needed,  whereas  in  the  electric  light, 
though  the  engine-power  is  doubled  in  "  thick"  weather,  yet 
the  ordinary  fair-weather  expense  of  the  engines  is  much 
greater  than  the  fair-weather  cost  of  the  gas  light-houses ; 
and,  further,  the  gradations  of  power  to  which  the  gas- 
light is  subject  are  much  more  varied  than  in  the  electric 
light,  and  the  former  can  be  suited  by  intelligent  keepers  to 
any  state  of  the  atmosphere. 
Absence  of  flex-  Of  course  the  oil-light  which  we  use  in  the  United  States 

light.  has  no  "  flexibility"  and  burns  the  same  in  fair  weather  as 

in  foul,  in  the  twilight  of  the  evening  as  in  the  darkness  of 
the  night.  This  is  a  fact  of  very  great  importance  in  this 
country,  and  particularly  in  high  latitudes  in  Great  Britain. 
In  the  long  twilights  of  the  last  summer,  while  between  the 
mouths  of  the  Tyne  and  Tweed,  I  found  no  difficulty  in 
reading  on  the  deck  of  the  Vestal  at  half  past  10  o'clock,  and 
indeed  it  could  hardly  have  been  said  to  be  dark  during  the 
entire  night.  In  these  long  twilights  and  in  clear  nights 
great  economy  can  be  attained  in  the  use  of  illuminating 
power,  which  can  be  stored  up,  as  it  were,  to  be  used  only 
when  the  weather  demands  that  it  shall  be  put  forth  in  all 
its  strength. 

Question  of  the     It  is  to  be  observed  in  this  connection  that  the  relative 
gVowers'of So penetratfflg  powers  of  the  oil,  the  electric  and  gaslights, 

noteiyett  dfteS have  not  yet  been  sufficiently  tested  at  a  distance  and  in  all 
sorts  of  weather.  This  is  a  matter  of  great  importance,  and 
should  be  made  the  subject  of  an  exhaustive  series  of  ex- 
periments. 

Almost  any  illuminant  is  good  enough  for  fair  weather, 

but  the  light  which  will  be  finally  adopted  by  all  nations 

will  be  that  which  will  send  its  rays  to  the  greatest  distance 

in  storm  and  thick  weather. 

illustration  of     Tne  gas  referees  of  London,  to  whom  the  English  Board 

of°London?feree8of  Trade  have  referred  the  matter  of  light-house  illumina- 
tion by  gas,  very  cleverly  illustrate  this  desideratum  as  fol- 
lows : 

"  Suppose  the  case  of  two  regiments  armed  in  the  main 
with  short-range  rifles,  but  each  comprising  a  body  of 
marksmen  twenty  in  number  in  one  regiment,  and  forty  in 
the  other,  armed  with  rifles  of  the  longest  range. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  113 

{i At  1,200  yards  the  power  of  these  regiments  would  be 
represented  solely  by  the  numbers  of  their  long-range  rifle- 
men— the  power  of  the  one  at  that  distance  being  double 
that  of  the  other,  although  at  close  quarters  their  destroy- 
ing-power would  be  equal. 

u  Every  flame  of  gas  or  oil  inaj7  be  said  to  be  a  sheaf  of 
rays  of  various  lengths  or  penetrating  power,  so  that  two 
lights  which  are  equal  near  to  their  source  may  become  un- 
equal when  viewed  from  a  distance;  and  an  analogous  effect 
to  that  of  distance  will  be  produced  by  mists  and  fog,  ob- 
stacles wmi  which  it  is  most  desirable  that  light-houses 
should  be  able  successfully  to  contend.'7 

THE  NEWARP  LIGHT-SHIP. 

This  light-ship  marks  one  of  the  sands  which  form  a  per-    Position. 
feet  labyrinth  off  the  coast  of  Norfolk  and  Lincolnshire.     It 
is  built  of  wood,  is  registered  as  212  tons  builders'  measure-    Material    ami 
ment,  and  has  three  masts  carrying  fixed  lights;  the  fore 81Lights. 
and  mizzen  being  24,  and  the  main-mast  light  34  feet  above 
the  sea.     It  is  anchored  in  17  fathoms  of  water  by  an  anchor    Moorinas 
weighing  45  cwt.,  having  210  fathoms  of  IJ-inch  chain,  and 
carries  besides,  two  bower-anchors  of  20  and  14  cwt.  re-- 
spectively,  with  150  fathoms  of  chain  each. 

The  ship  carries  a  Daboll  fog-trumpet,  which  is  sounded  by  e^abo11  trnni 
means  of  an  Ericsson  hot-air  engine  with  an  18-inch  cylin- 
der, placed  below  the  deck  and  near  the  bow  of  the  vessel. 
Both  the  smoke-funnel  and  the  trumpet  are  placed  forward 
of  the  foremast.  The  latter,  which  is  removable,  is  kept 
below  deck  when  not  in  use;  when  sounding  it  revolves 
once  a  minute. 

A  Chinese  gong  is  provided  for  use  in  case  of  accident  to    Chinese  gon- 
the  trumpet  or  engine,  and  it  was  sounding  when  we  leftpr 
the  vessel,  but  we  ran  out  of  its  range  at  a  very  short  dis- 
tance; I  thought  it  inferior  to  the  bells  used  in  our  light- 
ships. 

The  trumpet  was  also  sounded  after  we  left  the  vessel,  Trnmpetsound- 
and  although  I  judged  it  to  be  pitched  at  too  high  a  note, 
according  to  the  conclusions  arrived  at  in  our  American  ex- 
periments, we  heard  it  with  remarkable  distinctness.  At  a 
distance  of  two  miles  it  sounded  very  loud  and  clear ;  at  six 
miles  the  sound  had  sensibly  decreased,  but  it  was  quite 
audible  when  the  Vestal  was  under  way,  and  it  was  not 
until  we  had  gone  eight  miles  that  it  ceased  to  be  heard.  mi^gard  at  eight 

There  was  no  wind  to  interfere  with  the  sound,  but  my    Fog-si  Kuais 
experience  on  this  occasion  satisfied  me  that,  for  localities  5|w^hi8^.ry  °" 
where  fogs  are  as  prevalent  as  at  the  stations  occupied  by 
S.  Ex.  54 8 


114 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


our  light-ships  off  our  northern  coast  and  in  Long  Island 
Sound,  powerful  fog-signals,  operated  by  steam  or  hot-air, 
would  be  extremely  useful  to  the  immense  commerce  depend- 
ing on  these  vessels  for  safety. 

Arrangements  In  order  to  assist  in  determining  at  night  the  direction 
n!astshts  °n  thein  which  light-ships  are  riding  at  their  anchors,  the  lights  on 
the  mizzens  are  placed  at  lower  elevations  than  those  on  the 
main  masts. 

English  light-  In  the  English  service  each  light-ship  has  the  following 
ships' crews.  crew :  one  master,  one  mate,  three  lamp-lighters,  and  six 
able  seamen,  one  of  whom  may  be  a  carpenter.*  ISTO  appli- 
cants under  thirty -two  years  of  age  are  admitted. 

Table  of  rates     The  following  table  shows  the  uniform  rates  of  pay  in  the 

of  pay. 

service : 


i 
1 

sl* 

1 

'g'FrS 

Kate  per  month. 

p 

ci| 

. 

o 

^    S-i  '"w 

1 

^> 
p 

III 

£  s.  d. 

£  S.   d. 

£  s.  d. 

Masters,  uninsured                                             

6  13    4 

000 

000 

Masters   insured 

6  15  10 

050 

000 

Masters  who  have  served  as  such  five  years  and  up- 

ward            .                 .                 

526 

050 

000 

Masters  who  have  served  as  such  under  five  years  .  .  . 
Carpenters  who  have  served  as  such  five  years  and 

4  10    6 

050 

000 

upward         

3  11     0 

050 

026 

Carpenters  who  have  served  as  such  under  five  years 
Lamp-lighters  who  have  served  as  such  five  years  and 

386 

050 

0    2    G 

upward      

376 

050 

026 

Lamp-lighters  who  have  served  as  such  under  five 

years  .                                                        

330 

050 

026 

Seameu  who  have  served  as  such  five  years  and  up- 

ward 

300 

050 

026 

Seamen  who  have  served  as  such  three  years  and 

2  17    G 

050 

026 

Seamen  who  have  served  as  such  under  three  years  .  . 

2  17    G 

050 

000 

Table     of    ra- 
tions. 


Uniform. 


The  master  furnishes  the  provisions  per  the  following 
table : 

Meat,  10  pounds  per  week  each  man. 

Bread,  7  pounds  per  week  each  man. 

Flour,  2  pounds  per  week  each  man. 

Peas,  1  pint  per  week  each  man. 

Potatoes,  7  pounds  per  week  each  man. 

Suet,  J  pound  per  week  each  man. 

Tea.  2  ounces  per  week  each  man. 

Sugar,  f  pound  per  week  each  man. 

Beer,  3  gallons  per  week  each  man. 

When  on  shore  is.  Id.  per  day  is  allowed  each  man  in  lieu 
of  provisions. 

The  master  and  mate  are  furnished  a  regulation  uniform- 
suit,  and  the  crew  a  cap,  one  shirt,  and  one  pair  of  trousers 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  115 


annually.  When  unfit  for  longer  service  they  receive  a  pen- 
siou,  computed  on  length  of  service,  varying  from  4J$.  to  Is. 
per  day.  Their  pay  and  allowances  for  this  service  is  much 
better  than  those  of  either  the  royal  navy  or  the  merchant- 
service. 

Either  .the  master  or  mate  must  remain  on  board.     On 
third  of  the  crew  is  on  shore  at  a  time,  the  relief  occurring  once  third?  of  c™w  *° 

remain  on  board. 

a  month.  They  must  remain  near  the  shore-station,  with 
the  officer  (master  or  mate)  on  shore  at  the  time,  and  execute 
such  service  as  may  be  required,  and,  if  the  vessel  goes 
adrift,  join  her  as  soon  as  possible.  If  vessels  are  observed 
in  distress  guns  are  fired,  and  if  at  night,  rockets  are  thrown  • 
until  assistance  approaches.  Careful  and  regular  observa- 
tions  with  meteorological  instruments  are  taken  on  light  be  taken- 
vessels  as  well  as  at  light-houses. 

The  officer  in  charge  on  light-ships,  at  light-houses,  and  in 
the  Trinity  House  yachts  are  required  to  assemble  the  men  church-service. 
under  his  orders  every  Sunday,  (when  they  have  no  oppor- 
tunity of  attending  church,)  and  to  read  the  church-service  for 
the  day  and  a  sermon  or  homily  from  a  volume  provided  by 
the  Trinity  House  for  the  purpose  ;  when  one  of  the  Elder    orany  member 
Brethern  is  present  on  Sunday  the  church-service  is  read  by  re^prlS^" 
him. 

THE  COCKLE  LIGHT-SHIP. 

This  light-ship,  which  we  visited  on  our  return  from  the    Position. 
north,  is  placed  at  the  northern  entrance  to  Yarmouth 
Eoad.    It  is  155  tons  measurement,  is  built  of  wood,  and  is     Material, 

measurement, 

anchored  in  seven  fathoms  of  water.    It  carries  a  revolving  and  moorings. 
white  light  which  is  produced  from  nine  reflectors  arranged 
on  three  faces  ;  three  reflectors  on  each.    The  interval  be- 
tween flashes  is  one  minute. 

This  is  one  of  several  light-ships  of  this  kind  which  I  saw    Preferable    to 
in  my  journeys  around  the  English  and  Irish  coasts,  and 
they  are,  no  doubt,  much  more  useful  in  attracting  the  at- 
tention of  the  mariner  than  light-ships  with  fixed  lights. 

We  passed  the  Cockle  at  night,  and  I  had  a  good  oppor-    Daboiitmmpet 
tunity  of  seeing  the  light.    It  lies  about  six  miles  from  the  NewanTd  heard 
Kewarp,  and  the  crew  state  that  in  light  winds  and  clear  SxmSes.  Cockle> 
weather  the  Daboll  trumpet  of  the  latter  can  be  heard  with 
great  distinctness,  but  that  fog  "  kills  "  the  sound  to  a  great 
degree. 

SPURN  POINT. 

Spurn  Point  is  a  low  sand-spit,  projecting  into  the  mouth    Range-lights. 
of  the  river  H  umber.    There  are  two  towers  at  this  station, 
and  they  form  a  double  range  or  "  lead/'  the  outside  one 


116 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


Number 

ranffe-lights 


being  effected  by  the  eclipse  of  the  inner  light  by  the  outer 
tower. 

<^f  The  number  of  stations  on  the  east  coast  of  England 
.  with  two  towers,  many  of  them  with  first-order  lights,  form- 
ing ranges  or  leads,  is  noticeable,  and  is  accounted  for  by 
the  intricacies  of  the  channels  between  the  sands  and  shoals 
off  the  coast,  and  their  distance  from  the  land. 

hiShDtowertion°f  The  hi3n  or  main  tight-tower  was  built  in  1776  by  John 
Smeaton,  the  builder  of  the  Eddystone  light-house,  and  is 
as  unlike  the  graceful  light-house  towers  of  the  present  day 
as  can  well  be  imagined. 

The  rooms  are  very  large.  The  lower  story 'only  is  arched 
over,  and  is  used  for  an  oil-room,  while  the  upper  rooms 
serve  for  the  families  of  the  keepers,  and  one  is  used  as  a 
for  chapel  for  the  keepers,  coast-guardsmen,  and  fishermen  who 
live  at  the  Point. 

The  lens  is  of  the  first  order,  and  a  part  of  the  arc  of 
illumination  is  covered  by  white  light,  while  certain  dangers 
are  marked  by  a  red  sector.  The  red  glass  in  this  light 
covers  the  required  arc  of  the  lens,  and  is  fastened  to  its 
frame,  but  in  order  to  sharpen  the  "  cuts  "  between  the  red 
and  white  light,  narrow  strips  of  red  glass  are  placed  in  the 
lantern  opposite  the  edges  of  the  red  glass  outside  the  lens, 
as  is  shown  in  Fig.  7,  in  which  a  a  a  is  the  shade  of  red 


i-eeberspel 


Lens, 


Red  cut. 


house  list. 


Red  cut  at  Spurn  Point. 

glass  of  the  entire  height  of  the  lens  ;  1)  1)  vertical  strips  of 
red  glass  for  the  purpose  of  intensifying  the  "  red  cut  ;?  c 
the  lamp,  a  the  sector  of  red  light. 

f  Tlie  foUowing,  copied  from  the  British  light-house  list,  will 

suggest  the  purpose  of  this  mode  of  covering  by  red  light 
any  desired  area,  and  of  marking  by  the  cuts  between  the 


Hgh 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  117 

red  and  white  lights  any  line  upon  the  sea  within  the  circle 
of  illumination  : 

u  SPURN  POINT. — A  sector  of  red  light  is  thrown  from  the 
high  light-house  bearing  from  N.  W.  by  N.,  (cutting  two  cables 
•N.  E.  of  the  Sand  Hayle  buoy,)  round  northerly  to  S.  E.  by  E. 
J  E.,  on  which  bearing  it  ivill  cut  one  cable  north  of  Grimsby 
Pier.  In  other  directions  the  light  is  white." 

The  oil  in  use  at  this  station  when  I  visited  it  was  colza,    Coiza-oii  used. 
bat  I  believe  it  is  the  intention  to  change  this  and  all  the    Mineral  to  be 
other  lamps  in  the  service  of  the  corporation  of  Trinity ST3 
House  for  the  use  of  mineral-oil. 

The  lantern  was  a  fine  one  of  gun-metal,  the  sash-bars    Lantern. 
being  diagonal.     The  diameter  is  14  feet. 

The  service-room  was  fitted  up  with  closets  and  shelves,    service-room. 
and  the  articles  for  daily  use  are  neatly  stowed  away  in 
boxes  marked  "Cleaning-cloths,"  u Skins,"  " Powder  and 
brushes,"  u  Cotton  wicks,"  u  Polishing-powder  for  brass  and 
copper,"  &c. 

The  lens  is  supported  by  the  lantern-floor,  which  is  carried    Lens, 
upon  eight  double  iron  brackets,  and  the  interior  of  the 
watch-room  is  finished  in  corrugated  iron. 

The  station,  comprising  the  lower  dwelling,  &c.,  is  sur-    wall   Around 
rounded  by  a  high  wall  similar  to  that  at  the  Longstone, 
(mentioned  farther  on,)  but  for  a  different  purpose,  viz,  to 
keep  out  the  drifting  sand. 

The  lower  light-house  is  a  comparatively  new  structure,    L ow e r  light- 
and  was  built  in  shoal  water  inside  the  main  tower,  as  a  sub- 
stitute for  the  tower  which  Smeaton  built  outside  the  high 
light  which  was  some  years  ago  undermined  and  destroyed 
by  the  sea. 

The  apparatus  in  this  tower  is  of  the  fourth  order.  Apparatus. 

FLAMBOROUGH  HEAD. 

This  part  of  the  Yorkshire  coast  is  high  and  bold,  resem-    Appearance  of 
bling  the  coast  of  California. 
I  was  interested,  not  only  in  the  inspection  of  the  fine    oui  tower  for 

.     _X  .  burning  coal  still 

new  tower  on  this  remarkable  headland,  but  in  seeing  near  standing. 
by  a  well-preserved  example  (built  in  1674)  of  one  of 
those  great  coal-burning  light-towers  whose  use  preceded 
the  invention  of  either  of  the  systems  of  illumination  now 
in  use;  from  this  tower  was  witnessed  the  naval  battle 
between  the  Serapis  and  the  Bon  Homme  Richard,  which 
was  fought  off  this  headland  on  the  23d  of  September,  1799. 


118  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Height  of  focal  The  focal  plane  of  the  new  tower  is  214  feet  above  the  sea, 
and  87  feet  above  its  base.  The  tower  is  surmounted  by  a 

Characteristics 

of  lens.  first-order  revolving  lens,  showing,  alternately,  one  red  and 

two  white  Cashes. 

Quality  of  lens,     This  lens,  made  by  Chance,  Brothers  &  Co.,  of  Birming- 
ham, is  a  fine  piece  of  workmanship,  and  the  Trinity  House 
officers  state  that  all  of  the  optical  apparatus  furnished  by 
this  firm  give  great  satisfaction. 
Areas  of  red     The  area  of  each  of  the  red  panels,  is  to  the  area  of  each 

ami  white  panels.  J 

of  the  white  panels  of  the  lens,  as  21  to  9,  thereby  pro- 
ducing an  equalization  of  the  distances  at  which  the  flashes 
can  be  seen. 

Lamp-  The  lamp  was  one  of  the  latest,  combining  all  of  Dong- 

lass's  improvements,  and  burned  mineral-oil,  though  it  is 
suited  also  for  burning  colza. 

The  lantern  is  of  the  same  character  as  that  at  Hais- 
borough,  which  I  have  described,  and  there  were  no  points 
of  special  interest  at  this'station  that  were  not  mentioned  in 
connection  with  that  light,  except  that  on  the  edge  of  the 

ti(?D0gguI  a  bluff  there  is  a  fog-gun  station,  in  charge  of  a  special  set 
of  keepers,  (two,)  who  have  dwellings  and  gardens  separate 
from  those  at  the  light-station. 

^ Jog-gun,  how  The  gun,  an  18-pounder,  is  in  a  small  masonry  building 
having  an  embrasure  on  the  sea-side 5  it  is  fired  at  intervals 
of  fifteen  minutes  in  foggy  weather,  the  charges  being  three 
pounds.  About  one  thousand  rounds  are  fired  annually, 
and  they  are  kept  in  ready-filled  cartridges  in  barrels  in  the 
magazine.  The  gunners  have  no  other  duties. 

WHITBY. 

These  two  first-order  lights  are  on  the  coast  of  Yorkshire, 
and,  like  the  Haisborough  lights,  form  a  range  or  head 
which  clears  a  dangerous  rock. 

The  towers  are  about  250  yards  apart.    A  red  cut  shown 

Red  cut. 

from  the  northern  tower  covers  certain  other  dangers  to  be 
avoided  by  vessels. 

Fastening  for  The  mode  of  fastening  the  red  panes,  so  that  they  can  be 
easily  removed  for  cleaning  the  lens,  is  very  simple,  as  will 
be  seen  in  Fig.  8,  consisting  of  a  turning-plate,  which,  when 
shut,  rests  on  a  slight  projection. 

Another  simple  contrivance  in  use  was  a  movable  metal- 
lic guard,  which  is  slipped  over  the  burner  before  the  wick 
is  trimmed,  so  as  to  catch  the  cuttings.  (See  Fig.  9.) 

The  stairs  leading  from  the  watch-room  to  the  lantern 
were  noticeable,  the  step,  newel-post,  and  ornamental  bracket 
being  cast  in  one  piece. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


119 


The  smoke-pipe  leading  from  the  watch-room  stove  was    smoke-pipe. 
of  brass  neatly  burnished. 

The  dwellings  for  the  keepers  (each  light  having  two)  in^8eeper8' dwe11' 
were  placed  on  opposite  sides  of  each  tower,  and  the  rule  is 
general  that  each  keeper  has  a  dwelling  quite  separate  and 
detached  from  any  other. 

Fig.  8. 


Fastening  for  red  panes. 

The  dwellings  at  Whitby — and  this  is  also  the  rule — are 
only  one  story  in  height. 

There  was  nothing  noticeable  in  regard  to  the  lenses, 
except  the  large  amount  of  rear  light   (i.  e.  through  an  arc 
of.  180°)  not  utilized,  and  I  was  informed  that  formerly  the    Reflector   for- 
land  side  of  the  lens  was  occupied  by  a  metallic  reflector,  throwmgtberear 
which,  reflecting  the  heat  as  well  as  the  light  from  the  flame,  lfi 
caused  the  wick  to  burn  so  much  more  freely  on  the  rear 
side  than  on  the  other  as  seriously  to  impair  the  light. 

Fig.  9. 


r    MlllliyHlllllllUI] 


Lamp-guard. 

Totally  reflecting  glass  prisms,  such  as  are  now  used  in 
light- houses,  would  not  produce  this  effect,  but  they  have 
not  as  yet  been  supplied. 

I  learned  at  Whitby  that  one  of  the  light-keepers  has  dis-    Method  of  pre- 

paring     g  1  n  s  s 

covered  in  his  experience  that  dipping  the  lamp-chimneys  in  chimneys  to  re- 
a  hot  solution  of  soda  will  prevent  them  from  breaking 
even  when  exposed  to  the  strongest  flames. 


120 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Town  of  "Whit-     Not  far  from  the  light-bouse  is  the  town  of  Whitbv*  inter- 

V 

Euinsof  Abbey  osting  ouaccount  of  the  ruin  of  the  once  handsome  Abbey  of 
Saint  Hilda,  (founded  A.  D.  657,)  the  extensive  commerce 
in  jet,  mined  from  the  cliffs  near  by,  and  as  being  the  port 
from  which  Captain  Cook  sailed  in  his  voyage  of  discovery. 


of  saint  mida. 


SOUTER  POINT 

The  great  electric  light  at  Souter  Point,  which  I  visited 
on  our  return  voyage  from  the  north,  and  a  general  view 
of  which  is  given  in  Fig.  10,  is  three  miles  below  the  mouth 
of  the  river  Tyne,  and  I  reached  it  by  carriage  from  South 
Shields,  after  a  hurried  inspection  of  Sir  William  Armstrong's 
o  r  d  n  a  11  «•  e-  great  ordnance-works  at  Newcastle,  with  Admiral  Collinson, 

works  of  Sir  Will-  ,  . 

iam  Armstrong,  to  whom  I  am  indebted  for  the  permission  which  he  had 


thoughtfully 
London. 


permission 
obtained  from  Sir  William    before   leaving 


Fig.  10. 


Qn 


View  of  Souter  Point  Light-house. 
banks  of  the  river,  from  the  mouth  to  New  Castle 


Manufactories, 

and      effect      of  ,  „  „ 

smoke  therefrom.  aiKi  beyond,  there  is  an  immense  number  of  manufactories 
of  all  kinds,  and  their  smoke  hangs  over  the  river  like  a 
cloud. 
sea-approaches     When  the  wind  is  from  the  westward  this  smoke  is  driven 

obscured  by  .  1^41 

smoke.  over  the  sea-approaches  to  the  river,  obscuring,  much  to  the 

annoyance  of  the  great  number  of  vessels  of  all  classes  contin- 
ually entering  or  leaving  the  river,  not  only  the  pier-lights 
at  its  mouth,  but  the  sea-coast  light  at  Souter  Point  which 
indicates  the  general  position  of  the  harbor. 


SOUTER   POINT    LIGHTHOUSE!. 
ELECTRIC  LIGHT. 


PLATE  IX. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  121 

Fogs  on  this  part  of  the  east  coast  of  England  are  also    Frequency   of 
frequent,  and  as  they  mix  with  the  smoke,  the  problem  of  Oi 
light-house  illumination  of  the  sea  near  the  mouth  of  the 
Tyrie  is  one  of  great  difficulty. 

To  meet  it;  an  electric  light  was  constructed  at  Souter    Lightatsouter 

Point  one  of  the 

Point  a  few  years  ago,  and  it  is  without  doubt  one  of  the  most  powerful  in 

the  world.     • 

most  powerful  lights  in  the  world. 

The  condensed  beams  from  the  most  powerful  fixed  and  orj™e™  °f  £  "a" 
Hashing  first-order  sea-coast  lights  of  England  (with  the  (English.) e 
Douglass  four-wick  burner,  the  illuminant  being  oil)  are 
respectively  equal  to  9,000  and  to  111,000  candles,  (ours  are 
much  less,)  while  the  condensed  beam  of  the  flashing  electric    Power  of  light 
light  at  Souter  Point  (assuming  the  power  of  the  lens,  asat 
calculated  by  Mr.  Chance,  to  be  196  times  as  great  as  the 
power  of  the  unassisted  light)  is  equal  in  power  to  800,000 
caudles ! 

That  even  this  intense  light  fails  to  penetrate  a  dense  fog 
I  know  from  my  own  experience,  which  I  will  relate  furtherig, 
on,  and  it  is  not  surprising,  since  the  sun  itself  cannot  do  so; 
but  that  it  meets  the  requirements  of  those  intermediate 
conditions  of  u  thick  weather,"  between  fair  weather  and  im- 
penetrable fog,  as  well  as  can  be  asked  for  any  possible  sea- 
coast  light,  cannot  be  doubted,  although,  considering  "  flex-  Question  of  8U. 
ibility  "  *  as  well  as  power,  I  believe  it  yet  a  question  which  JJgJj 
of  the  two,  the  gas  or  the  electric  light,  may  be  the  better. 

The  lens  at  Souter  Point  is  of  the  size  of  those  of  the  third 
order,  or  39.38  inches  in  diameter,  and  consists  of  a  fixed- 
light  apparatus  covering  the  sea-horizon,  i.  e.,  180°,  and  is 
surrounded  by  eight  panels  of  vertical  condensing-prisms, 
which  in  their  revolution  give  flashes  at  intervals  of  one 
minute. 

The  lenticular  apparatus  is  a  very  beautiful  piece  of  work-  ch^Tce,  B?othebre 
manship,  and  much  credit  has  been  obtained  by  the  manu-  &c°- 
facturers,  Chance,  Brothers  &  Co.,  for  their  skill  and  in- 
genuity in  disposing  the  rays  of  the  electric  spark  to  the 
best  advantage  to  this  locality. 

The  electric  spark  used  for  purposes  of  light-house  illumi:8  ^  electric 
nation  differs  from  other  sources  of  light  in  the  smallnessof 
its  dimensions,  and,  within  certain  limits,  its  variability  in 
position. 

The  former  feature,  although  requiring  that  the  apparatus 
shall  be  specially  designed  for  its  use,  is,  in  the  hands  of  alights. 
competent  optical  engineer,  a  most  valuable  characteristic. 
It  is  possible  to  direct  and  distribute  light  from  a  point 
almost  as  one  wishes  and  without  waste,  but  the  conse- 

*  See  Haisborough  gas-light. 


122  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

quences  of  any  error  in  designing  or  executing  the  optical 
apparatus,  are  even  more  serious  and  far  more  apparent 
than  when  a  larger  source  of  light  is  used. 
Accidents  to  re-     it  is  a  fact  important  to  be  noted  that  at  this  station,  as 

volvmg  appara- 
tus provided  for.  at  all  others  in  the  English  service,  the  contingency  of  ac- 
cident to  the  clock-work  carrying  the  revolving  lens  is  pro- 
vided for.  A  crank  for  turning  it  by  hand  can  be  attached, 
and  a  dial  placed  before  the  keeper  indicates  the  velocity 
of  revolution,  so  that  he  has  no  difficulty  in  preserving  the 
proper  intervals  between  the  flashes. 

utilizing  the  A  part  of  the  light  thrown  to  the  rear  (toward  the  land) 
is  taken  up  by  an  annular  refracting  lens  surrounded  by  ca- 
tadioptric  prisms,  the  whole  being  about  15  inches  in  diam- 
eter and  forming  a  holophote  of  the  sixth  order,  and  the  rays 
after  passing,  being  formed  into  a  cylindrical  beam  of  paral- 
lel rays,  impinge  against  a  set  of  totally  reflecting  straight 
pirisms,  which  in  turn  cast  them  at  right  angles,  in  a  beam 
of  parallel  rays,  down  through  a  vertical  wooden  tube,  pass- 
ing through  a  circular  aperture  in  the  floor,  upon  another 
set  of  totally  reflecting  prisms  in  the  room  below,  and  they 
again,  turn  the  rays  at  right  angles  and  out  through  a  large 
e  r  s  plate-glass  window  upon  some  dangers  southward  of  the 
point,  which  are  called  "  The  Mill  Rock,"  "  Hendon  Rock," 
and  uThe  White  Stones."  (See  Plate  IX,  which  is  a* chart 
showing  Souter  Point  and  its  vicinity.) 

The  window  through  which  this  borrowed  light  passes  is 
divided  vertically  into  two  parts,  the  one  on  the  western  or 
land-side  being  red  and  the  other  white ;  the  line  of  divis- 
ion  being  produced  over  the  sea  gives  a  "red  cut,"  the 
utility  of  which  will  be  understood  from  the  following  sail- 
ing-directions, taken  from  the  British  light-house  list : 
Sailing  direc-  "  SOUTER  POINT.— T/itf  main  light  is  electric  and  flashes 
every  minute.  A  fixed  light,  also  electric,  is  shown  21  feet 
below  the  flashing  light,  and  shows  white  between  the  bearings 
of  N.  by  W.  and  N.  J  E.,  and  red  between  N.  £  E.  and  N. 
by  E.  f  E.  When  the  fixed  white  light  is  seen,  vessels  will  be 
in  line  of  Mill  Rock  and  Cape  Carr 'Point,  and  when  it  chancjes 
to  red,  in  that  of  Whitburn  Stile,  Hendon  Rock,  and  White 
Stones." 

Plate  x.  Plate  X  shows  a  plan  of  the  lower  light-room  and  details 

of  the  window  through  which  the  "  red  cut "  is  made,  a  in 
the  plan  showing  the  position  of  the  lower  refracting  prisms. 
Plate  XL  The  engine-room,  a  plan  of  which  is  shown  in  Plate  XI, 

with  its  accessories,  (including  fuel-rooms  for  the  storing  of 
coke,  of  which  about  100  tons  are  used  annually,)  and  the 
dwellings  of  the  keepers  form  a  large  quadrangle,  (see  Plates 


SCALE  TOR  PL  AN 


SECTION  OF  WINDOW  A. 

SCALEroa  DETAILS. 


SOUTER    POINT    LIGHTHOUSE. 

ELECTRIC  LIGHT. 
PLAN    OF  MACHINE-ROOM. 


PLATE  XI 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  123 

XII  and  XIII,)  the  former  being  on  the  land-side,  while,    piatesxiiand 
toward  the  east  or  seaward,  is  the  tower,  which  is  detached  . 
from  the  rest  of  the  establishment,  except  that  communica- 
tion is  had  by  a  covered  way  one  story  high. 

The  machinery  for  generating  the  electric  current  is  simi-    Machinery. 
lar  to  that  at  South  Foreland. 

Two  rotary  magneto-electric  machines  of  Professor  Holmes'    Magneto-eiec- 

.    ,  tricmachinesand 

patent  are  driven  by  two  3  horse-power  engines  which  can  engine, 
be  worked  up  to  6  horse-power  each. 

Each  machine  consists  of  eight  radial  frames,  to  each  of   construction  of 
which  are  attached  36  magnets,  making  288  in  all,  and  the the  machine8- 
poles  are  alternately  pointed  toward  and  from  the  axis  of 
the  machine. 

A  shaft  driven  by  the  engine,  revolves  a  series  of  cylinders    The  magnets. 
composed  of  helices  of  wire,  past  the  magnets,  which  pro- 
duce the  alternately  positive  and  negative  currents.    These 
currents  are  collected  by  the  wires  passing  up  the  tower  to  dl£™Jrent8   pro" 
the  electric  lamp  within  the  lens. 

The  number  of  revolutions  made  by  each  machine  per    Number  of  rev- 

jrvrt  T  i  -i          -i    -i  i  olutious  per  miri- 

imnute  is  400,  and  as  16  sparks  are  produced  by  each  mag-  ute  and  conse- 

net  at  each  revolution,  the  number  of  sparks  at  the  carbon  sparks™" 

points  of  the  lamp  is  6,400  per  minute,  when  one  machine 

only  is  in  operation,  as  is  the  case  in  fair  weather,  and  12,800 

per  minute  when  both  machines  are  at  work.    These  sparks 

are  formed 'so  rapidly  that  the  eye  does  not  separate  them, 

and  the  result  is  a  continuous  beam  of  light,  so  dazzling, 

that  the  eye  of  a  person  within  the  lantern  cannot  rest  upon 

it  for  an  instant,  without  intense  pain. 

To  insulate  the  shaft  of  the  machine  which  conducts  the  insulation  of 
electric  current  to  the  wires,  it  is  encased  in  ebony-wood 
journals,  and  where  the  wires  pass  through  the  wall  of  the 
engine-room  there  is  a  coupling-box  so  arranged  that,  by  a 
single  motion,  they  can  be  connected  or  disconnected,  and 
the  current  from  one  machine  or  two  can  be  turned  on  to 
the  lamp  at  pleasure. 

The  electric  lamp,  as  at  South  Foreland,  consists  mainly  Electric  lamp. 
of  two  carbon  points,  each  about  ten  inches  long  by  one- 
half  an  inch  square  in  section,  placed  end  to  end  in  a  ver- 
tical position,  and  the  automatic  machines  called  regulators, 
feed  the  points  toward  each  other  as  last  as  they  are  con- 
sumed, which  is  at  the  rate  of  one  inch  per  hour  each. 

An  oil-lamp  is  placed  under  the  electric  lamp,  and  is   on-iampforuse 
always  filled  and  ready  to  be  substituted  in  case  of  accident  den?80 
to  the  latter,  or  to  the  machinery  ;  but  I  did  not  learn  that 
a  necessity  for  its  use  had  ever  arisen. 


124 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

Plate  XIV  and  Fig.  11  illustrate  the  disposition  of  the 
different  parts  of  the  lenticular  apparatus  at  Souter  Point. 

In  the  former  a  is  the  focus  ;  a'  the  electric  lamp  ;  a"  a" 
the  carbon  pencils ;  b  the  holophote;  c  the  upper  totally 
reflecting  prisms ;  d  d  the  fixed  dioptric  apparatus ;  e  e  the 
revolving  frame  of  flash-panels ;  //  revolving  gearing;  g 
the  removable  bed-plate  ;  h  the  burner  of  the  oil-lamp  5  'i 
telescopic  tubes  for  the  supply  of  oil  and  the  overflow,  for 
use  if  the  oil-lamp  should  be  substituted  at  any  time  for  the 
electric  lamp  •  I  the  oil-reservoir;  m  m  the  oil-supply  pipe ; 
n  cylindrical  shaft  for  transmission  of  the  beam  of  reflected 
light  to  the  lower  light-room  5  o  the  lower  reflecting  prisms ; 
pp  the  window  of  the  lower  light-room;  g  a  gallery  used 
when  cleaning  the  sash  of  the  window. 

Tig.  11. 


Plan  of  lens  and  lantern,  Souter  Point. 

In  the  figure  a  is  the  focus  ;  b  the  holophote  ;  c  c  the  upper 
reflecting  prisms ;  d  d  d  the  fixed  dioptric  apparatus ;  e  e  e 
the  flash-panels.  The  dotted  circle  under  c  c  shows  in  plan 
the  shaft  for  transmitting  the  beam  of  reflected  light  to  the 
lower  light-room. 

The  tower  at  Souter  Point,  shown  in  Plate  XV,  is  built 
like  most  of  the  towers  I  saw  in  England,  being  a  shell  of 
brick- work  into  which  the  steps  are  let  at  the  outer  end 
only,  and  with  landings  at  the  windows. 


*    t 


<     I 


o 
n 

z 
n 

> 

r 

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r 


n 


r  r 

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H   . 

n 


SOUTER   POINT   LIGHTHOUSE 

ELECTRIC  LIGHT. 


PLATE   XIII, 


GROUND^  PLAN. 


IT.  Bret-Room*. 
tf.  tp.  fln-ft-fti  {.'wridors. 


o.  o.JZarthr  Closeif. 
p.  Coke-Store . 
q.JZoilers. 


i.i.  XcnlUriss. 


lp_      A    '     O  fO  20 


SCALE. 


t.t.Wo?>hshops. 
v.  Y.Worhbenches. 
o  Tja&it. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  125 

The  watch-room  floor  is  of  iron  and  supported  upon  a    watch-room. 
system  of  radiating  and  concentric  beams.     The  watch- 
room  is  fitted  up  with  supplies  for  use  in  the  lantern,  viz, 
oil,  burners,  and  chimneys,  and  skins  and  cloths  for  clean- 
ing the  metal- work  and  glass  of  the  lantern  and  lens. 

The  lantern  is  of  the  size  heretofore  described,  viz,  14    Lantern. 
feet  in  diameter,  and  it  has  diagonal  sash-bars  of  steel. 

On  the  cliff  in  front  of  the  tower  is  a  Holmes  fog-horn,  Fog-horn. 
sounded  in  foggy  weather  by  means  of  the  engine  for  driv- 
ing the  magneto-electric  machines.  An  ingenious  contriv- 
ance of  the  inventor  makes  the  down-strokes  of  the  plungers 
of  the  air-pump  slow  and  the  up-strokes  quick.  This 
done  by  means  of  three  eccentric  cog-wheels,  the  middle pump- 
one  (the  driving-wheel)  of  which  gives  motion  to  the  two 
others,  to  which  are  connected  the  shafts  of  the  pumps. 

The  cost  of  the  station  is  given  as  follows :  cost  of  station 

with  revolving 

Building- works £7, 150  $35,  750  electric  »ght. 

Lantern,  dioptric  apparatus,  &c 3,  436  17, 180 

Electric  apparatus,  machinery,  &c 4, 100  20, 500 

Miscellaneous 462  2,310 


15, 148  75,  740 

Deducting  about  £750  ($3,750)  on  account  of  difference 
in  cost  of  revolving  and  fixed  dioptric  apparatus,  and  also 
the  cost  of  revolving  machinery,  the  above  sum  would  indi- 
cate the  approximate  cost  in  England  of  a  fixed  magneto- 
electric  light. 

Electric  lights,  being  considered  more  important  than    The  best  keep- 
others,  receive  the  preference  in  appointment  of  keepers, Slfflciights.01 
and  the  most  competent  are  appointed  for  these  stations, 
their  salaries  exceeding  that  of  keepers  of  their  grade  at 
other  lights  10  per  cent. 

Each  electric  light-station  is  in  the  immediate  charge  of  a  r?"f ^i  kree  !er 
principal  keeper,  who  is  called  an  engineer. 

At  South  Foreland,  where  there  are  two  lights,  six  assist-  ke?pe£  bat  reiecf 
ants  are  allowed ;  at  Dungeness,  five ;  and  at  Souter  Point, tric  light8- 
four. 

At  these  lights  the  engineer  has  sole  charge,  and  is  ustati°?    in 

charge  of  the  en- 

responsible  for  the  premises,  property,  and  stores,  as  well  gineer. 
as  for  the  proper  service  and  efficiency  of  the  light.  When 
he  is  absent  the  senior  assistant  takes  his  place.  He  is  not 
required  to  keep  watch,  but  must  visit  the  lantern  and 
engine-room  at  various  times  during  the  night,  besides  the 
regular  visits  at  the  end  of  each  four-hour  watch;  and 
must  always  be  present  in  the  engine-room  when  preparing 
for  lighting. 


126  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

watches  of     The  assistants  take  equal  watches  of  four  hours  each,  one 

keepers   at  elec-         ,  ,  .  -.  .       ,  .       , 

trie  lights.         in  the  engine-room  and  one  in  the  lantern. 


boFie?sincs  and  ^^e  engines  an(l  boilers  are  worked  alternately,  one  each 
week.  Steam  is  to  be  up  in  one  boiler  (the  other  boiler 
being  filled  and  the  fire  ready  for  lighting)  and  the  mag- 
neto-electric machines  ready  for  starting  five  minutes  before 
nd°f  extin  "  sunse^  ^ne  lamP  is  lighted  at  sunset  and  extinguished 
at  sunrise. 

In  case  of  accident  to  any  part  of  the  electric  apparatus. 
the  oil-lamps  must  be  immediately  substituted  for  the  electric 
lamps,  and  to  keep  them  in  perfect  order,  it  is  required  that 
they  be  lighted  and  kept  perfectly  in  focus  for  one  hour 
(during  the  day)  once  a  week. 

observation  of     After  leaving  the  Tyne  at  night  we  stood  off  from  Souter 

lt-  Point  to  observe  the  light  from  the  sea,  and  it  certainly 

surpassed  in  brilliancy  any  I  have  ever  seen,  being  so 

bright  that  at  a  distance  of  several  miles  well-defined  shad- 

ows were  cast  upon  the  deck'of  the  Vestal. 

effectso7thl  red     We  afterward  took  the  pinnace  of  the  Vestal  and  steamed 

cut  into  the  white  and  the  red  lights  from  the  low  light,  and 

across  the  "red  cut"  several  times  andin  different  directions. 

We  found  it  quite  well  defined,  so  that  no  vessel  in  a  clear 

night  when  observing  the  sailing-directions  could  get  into 

the  dangers  which  the  low  lights  are  designed  to  point  out. 

Admiral  Collinson  had  given  directions  to  have  the  fog- 

trumpet  sounded  when  the  keepers  should  observe  the  Vestal, 

but  we  were  probably  too  far  off  while  observing  the  light 

from  the  sea,  for  we  did  not  hear  it. 

Light  obscured     As  before  observed,  we  visited  this  light  on  our  return 

smoke6  (       a  voyage  from  the  north,  but  it  had  happened  that,  on  going 

to  the  north,  it  being  thick  and  rainy,  a  dense  cloud  of  fog 

and  smoke  shut  down  over  the  sea  before  we  arrived  off 

Souter  Point,  and  we  ran  in  toward  the  land,  passing  the 

light  as  we  supposed  within  three  miles,  but  did  not  see  it. 

Finding  our  position  after  reaching  the  mouth  of  the 

Tyne,  we  ran  back  toward  Souter,  and  in,  as  far  as  was 

thought  safe  on  account  of  the  dangerous  rocks  in  the  vicin- 

impossibiiityity,  but  still  could  not  see  the  light.    This  confirmed  the 

fog  byTnyriightg  opinion  of  the  Elder  Brethren  as  well  as  of  oursel  ves,  that 

there  is  no  light  which  will  penetrate  a  fog,  and  all  that  is 

possible  in  light-house  illumination  is  to  make  light  suffi- 

ciently powerful  to  be  depended  upon  in  all  sorts  of  thick 

weather  up  to  the  impenetrable  limit. 

utility  of  low     There  can  be  no  doubt  of  the  utility  of  the  low  light  and 
h-ins    and  red  the  u  re(j  cut  »  in  pointing  out  dangers  within  range  of  a 


SOUTER  POINT  LIGHTHOUSE. 

ELECTRIC  LIGHT. 


PLATE  XIV 


(0 

o 


r  * 

5  "* 
22 


o 

c* 
Fl 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  127 

light-house.  I  will  describe  a  more  marked  case  of  their 
application  at  Coquet  Island. 

Another  application  of  the  use  of  borrowed  light  has  sug-    Suggestion  as 
gested  itself  to  me.    It  is  this:  Our  sea-coast  lights  are  often  lights  on  our  own 
from  150  to  200  feet  above  the  sea,  and  it  frequently  hap- c' 
pens,  particularly  on  our  Pacific  coast,  that  a  fog  will  hang 
over  the  sea  and  shore  low  enough  to  envelop  a  light  at 
this  elevation,  and  yet  it  remains  clear  below  and  at  the 
level  of  the  sea. 

Where  the  tower  is  not  surrounded  by  water  and  there  is    Method  to  be 
a  laud-side,  as  is  almost 'always  the  case,  a  part  of  the  light  empi°: 
thrown  to  the  rear  or  landward  can  be  taken  up,  as  at  Sou- 
ter,  and  thrown  by  means  of  totally  reflecting  prisms  through 
a  tube  passing  down  the  tower  to  a  lens  placed  in  a  salient 
lantern  at  the  proper  distance,  say  15  or  20  feet  above  the 
foot  of  the  tower. 

In  my  description  of  lights  on  the  coast  of  Wales  will  be 
found  an  account  of  a  separate  low  light  for  foggy  weather 
in  actual  use. 

COQUET. 

This  interesting  light-house  is  on  Coquet  Island,  off  the    Position. 
coast  of  Northumberland,  and  is  of  the  first  order,  dioptric, 
the  lens  covering  about  270°  of  the  horizon. 

A  vertical  pane  of  red  glass  attached  to  the  lanteru  cov-    Red  light. 
ers  an  area  to  the  northward  with  red  light,  and  the  narrow 
Coquet  Eoads  inside  the  island  are  illuminated  by  the  lamp 
alone,  unassisted  by  lenticular  apparatus. 

Areas  both  to  the  northward  and  southward  are  purposely    Areas  shut  off 
shut  off  from  all  light  from  the  lens,  by  means  of  opaque  fr( 
panels  in  the  lantern,  the  object  being  to  warn  vessels  of 
their  proximity  to  danger  when  the  light  is  lost  sight  of. 

The  height  of  the  focal  plane  of  this  light  above  the  sea    Height  of  foca 
is  83  feet.  plane- 

.Below  the  watch-room  is  a  lower  light-room,  with  a  large    Lower    light- 
plate- glass  window  looking  to  the  southward,  and,  on  theroom' 
opposite  side  of  the  room,  near  the  middle  of  the  wall,  28 
feet  below  the  focal  plane  of  the  main  light,  is  a  catoptric 
apparatus,  consisting  of  three  reflectors  provided  with  lamps 
having  red  chimneys. 

The  jambs  of  the  window  limit  the  red  rays  emanating:    Limitation  of 

«  .  °  red  rays. 

from  these  lamps,  and  mariners  are  warned  to  use  great 
caution  in  approaching  the  shore  after  they  get  into  the  red 
light. 

For  the  further  purpose  of  marking  the  position  of  an  im-  dn^d  cu  *  pr 
portant  buoy,  a  red  "cut"  is  produced  by  means  of  a  fourth 


128 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

reflector  placed  near  the  northwest  corner  of  the  room,  which 
throws  a  beam  of  white  light  through  the  red,  the  cut  being 
made  at  the-  edge  of  the  ruby-glass,  with  which  a  part  of  the 
window  is  glazed.  This  red  cut  intensifies  the  cut  produced 
by  the  interception  by  the  east  jamb  of  the  window  of  the 
rays  from  the  three  red-light  reflectors. 

Fig.  12. 


Low-light  room,  Coquet  island. 

Figure  12  shows  the  arrangement  of  light  in  the  lower 
light-room  ;  a  is  the  single  reflector  for  white  light ;  &,  the 
three  reflectors  for  red  light,  placed  one  over  the  other,  but 
with  their  axes  slightly  divergent  in  plan ;  c,  a  vertical 
strip  of  red  glass,  the  western  edge  of  which  divides  the  light 
from  a  into  red  and  white  lights ;  $,  the  eastern  window- 
jamb  limiting  the  red  light  from  b-,  «,  the  sector  of  white 
light,  and  {3  the  sector  of  red  light  5  a  c  and  b  d  are  parallel. 

The  purpose  of  the  ingenious  arrangement  of  lights  in 
the  lower  light-room  will  be  better  understood  by  an  in- 
spection of  the  chart  in  Plate  XVI,  and  from  the  following 
sailing-directions : 

Sailing-air ec-  COQUET  ISLAND. — The  upper  light,  wliite,  is  visible  seaward 
between  the  bearings  from  the  sea  of  S.  by  W .  f  TT.,  and.N.  f 
K;  and  red  from  8.  by  W.  f  W.  to  S.  by  W.  %  W.,  to  cover 
the  Bulmer  Bush  and  Bulmer  Stile  rocks. 

"A  dim  white  light  from  the  naked  lamp  of  the  apparatus 
is  shown  between  the  bearings  S.  and  N.  E.  f  N".  to  cover  the 
anchorage  inside  the  island. 


tions. 


PLATE  XVI. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  129 

"A  second  light,  twenty-eight  feet  below  the  main  light,  is 
shown  from  the  same  tower.  It  is  white  beticeen  the  bearings 
from  the  sea  of  N.  by  W.  f  W.  and  N.  J  W.,  to  guard  the  shoal 
off  Rauxley  Point,  and  red  from  N.  %  W.  to  N.  by  E.$E.,  to 
cover  the  Bondicar  Bush  shoal. 

a  When  the  upper  light  is  lost  sight  of  westward  of  N.  f  E., 
the  line  of  Hauxley  Point  and  Bondicar  Bush  will  be  passed, 
and  while  in  the  low  red  light  great  caution  is  necessary  in 
approaching  the  shore"  Diviaion of the 

sea-area    around 

It  will  be  observed  that  the  sea  around  Coquet  Island  is  tho   light    into 
divided  into  eight  distinct  areas,  each  of  which  is  easily  e1' 
recognizable  by  an  inspection  of  the  lights ;  that  is  to  say,  in 
going  from  the  northward  round  by  the  eastward  and  south- 
ward, the  following  changes  are  seen : 

Bearings  of  tlie  light-house.         Appearances  of  the  lights. 


From  S.  21°  W.  to  N.  21°  W. 
From  N.  21°  W.  to  N.  6°  W. 


From  N.  GO  W.  to  N.  7°  E. 


From  N.  7°  E.  to  N.  15J°  E. 
From  N.  15£°  E.  to  N.  38°  E. 
From  N.  38°  E.  to  S.  1°  E. 

From  S.  1°-  E.  to  S.  17°  W. 
From  S.  17°  W.  to  S.  21°  W. 


Main  light  (only)  white. 
Both  the  high  and  low  lights, 

white. 
The  high  light  white,  the  low 

light  red. 

The  lower  light  (only)  red. 
No  light. 
Dim   high  light  unassisted 

by  lens,  white. 
No  light. 
The  high  light  (only)  red. 


Arrangem  e  n  t 
,  ,  •  _      of  lights  the  best 

The  mam  light  could  not  have  been  arranged  to  warn  the  that  could  be  had. 
mariner  of  the  near  dangers,  as  the  low  light  so  success- 
fully does,  since  the  former  must  throw  its  light  uniformly 
over  the  sea  and  many  miles  farther  to  the  southward  be- 
yond the  dangerous  rocks  and  reefs.  Tower  and 

The  tower  and  dwelling  at  Coquet  are  built  of  stone  and  dwelling- 
are  very  picturesque,  the  station  having  been  built  upon 
the  remains  of  a  Norman  monastery.  Buoy-depot. 

Adjoining  the  light-house  is  a  substantial  buoy-depot, 
and  a  well-built  wharf  is  provided  with  a  traveling-crane 
for  loading  and  unloading. 

The  lights  on  this  part  of  the  coast  are  under  the  super- Morton- 
intendence  of  Mr.  Morton,  whose  polite  attentions  I  desire 
to  acknowledge. 

S.  Ex.  54 9 


130  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

observing  While  lying  in  Coquet  Koads  I  went  at  night  with  Admiral 
th^seaatnight^Colliusou  in  the  steam-pinnace  to  observe  the  red  cut  of 
the  low  light  ;  its  utility,  which  had  been  explained  to  ine 
in  theory,  I  found  fully  confirmed  in  practice. 

visit  to  castle     j  am  aiso  under  obligations  to  the  admiral  for  an  oppor- 

01  Warkworth. 

tunity  of  visiting  with  him  one  of  the  most  interesting 
places  in  England,  the  ruins  of  the  once  magnificent  Castle 
of  Warkworth,  the  home  of  the  Percys,  which  is  a  few  miles 
from  the  landing-place  opposite  Coquet  Island. 

INNER  FARNE   ISLAND. 

Lights  form  a  There  are  two  lights  on  the  Inner  Fame,  which  is  off  the 
coast  of  Northumberland,  and  they  form  a  range  or  lead. 

characteristic  The  main  light  is  catoptric  and  revolving,  there  being  seven 
°  o?Tdw  ifgit.  reflectors,  (one  on  each  face.)  The  low  light  is  about  200 
yards  northwest  from  the  main  light,  and  contains  a  single 
fixed  reflector. 

Keeperof  main     The  keeper  of  the  main  light  watches  the  other  by  means 

light  watches  the 

low  light;  meth-  of  a  small  reflector,  which  catches  a  little  of  the  ligh  tof  the 
latter  and  throws  it  back  toward  the  lantern  of  the  main 
light  through  an  aperture  in  the  smaller  tower. 

chimneys.  The  only  peculiarity  to  be  observed  at  this  station  was 
the  chimneys  of  the  reflector-lamps,  which  had  no  shoulders, 
but  were  conical  from  top  to  bottom,  with  a  large  flare. 

THE    LONGSTONE. 

Themostnorth-     The  Outer  Fame  or  Longstone  light-house  is,  with  the 

ern  of  North  Sea  ,.  _  ..       .       ,.    .  ,       ,    _.  .    .          ,    ,  .  ,.        _ 

lights.  exception  of  a  small  pier-light  at  Berwick,  at  the  mouth  of 

the  Tweed,  the  most  northern  of  the  North  Sea  lights  of 
England,  and  is  in  view  of  the  light  on  St.  Abb's  Head,  the 
first  of  the  Scottish  lights. 

Construction.  j^  js  a  TOG^  light-house  of  the  peculiar  construction  shown 
in  Plate  XVII,  the  tower  and  dwellings  being  surrounded 
by  high  walls  to  protect  them  from  the  sea,  which  frequently 
rolls  with  great  violence  over  the  rock,  which  is  long  and 
narrow. 

LCDS.  A  new  first-order  revolving  lens,  made  by  Chance  Broth- 

ers &  Co.,  has  recently  been  placed  in  the  tower,  and  the 
entire  station  has  been  repaired  and  refitted,  the  mechanics 
being  still  at  work  at  the  time  of  my  visit. 

Light  seen  While  at  Coquet  Island  I  saw  this  light  very  distinctly 
the  deck  of  the  Vestal,  say  10  feet  above  the  sea,  at  a 


£.  °f         en  distance  of  twenty  miles,  which  was  remarkable,   as  the 
focal  plane  is  but  85  feet  above  the  sea. 


.Plate  XYIL 


* 


THE     LONGSTONE     LIGHT-HOUSE. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  131 

There  is  only  the  ordinary  number  of  keepers  (two)  at    Keepers. 
this  station,  but  they  are  supplied  with  provisions  from  the 
mainland  and  but  rarely  leave  the  rock. 

This  light-house  is  interesting  as  having  been  the  home  of   The  home  ot 
Grace  Darling,  the  daughter  of  a  former  keeper,  and  to Grace  Darling' 
whom  owed  their  rescue  the  nine  out  of  the  sixty-three  who 
were  on   the  Forfarshire  when   she  struck  the  "Hawker 
Kock,"  near  the  Longstoue,  on  the  5th  of  September,  1838. 

The  keepers  had  much  pride  in  showing  us  the  bed-closet 
occupied  by  the  heroine  and  the  window  through  which  she 
first  saw  the  wreck.    A  beautiful  tomb  is  erected  in  her    Tomb  of  Grace 
memory,  at  Bamborough  Castle,  near  by  on  the  mainland.  Darlm* 

The  foregoing  comprises  the  notes  of  my  journey  among    Thank8to  Ad 
the  lights  of  the  North  Sea,  and  I  must,  in  concluding  my 
account  of  it,  express  my  thanks  to  Admiral  Oollinson  and ler- 
Captain  Weller  for  their  unremitting  efforts  to  make  it  for 
me  a  journey  of  pleasure  as  well  as  of  profit. 

The  Vestal,  in  which  this  cruise  was  made,  is  a  handsome    Description  of 
sea-going  side- wheel  steamer,  about  the  size  of  our  supply  - 
steamer  Fern,  and  is  used  for  conveying  oil  and  other  sup- 
plies to  the  light-houses,  and  for  purposes  of  inspection. 

A  yearly  inspection  of  the  light-stations  is  made  by  some    Yearly 
of  the  Elder  Brethren  5  at  other  times  the  superintendent  in 
charge  of  each  district  inspects  the  stations  and  causes  the 
necessary  repairs  to  be  made. 

The  Trinity  House  has  several  of  these  steam  tenders,  or 
"yachts,"  as  they  are  called,  each  of  them  carrying  a  steam 
pinnace  or  launch  outboard. 

The  weight  being  too  heavy  for  the  davits,  two  swinging 
brackets  were  placed  under  the  bottom  of  the  launch  and 
stepped  upon  the  rail  of  the  steamer.  These  supports  can 
be  raised  or  lowered  by  means  of  a  screw-thread  and  a 
stationary  nut  in  the  rail. 

These  launches  are  of  much  utility  in  landing  stores  and    use  of  the  pin. 
towing  the  other  boats,  (of  which  the  Vestal  carries  four,) na 
and  they  steam  from  six  to  eight  knots  an  hour.    In  going 
to  beaches  or  rocks  the  launch  is  always  accompanied  by  a    Dingey  carried 

by  the  pinnace. 

dingey  ;  this,  as  does  each  of  the  other  boats,  carries  on  its 
thwarts  a  gang-plank,  which  is  made  with  a  triangular  cut 
at  one  end,  to  be  hung  over  and  against  the  stem  of  the 
boat.    These  gang-planks,  which  are  battened  on  the  upper    Gang-planks, 
surface,  and  are  about  10  feet  long,  are  found  to  be  very 
useful. 
The  Vestal  has  no  house  on  deck  except  a  small  one  over    House  on  deck. 


132  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

the  main  companion-way  to  the  saloon,  and  another  over 
the  galley  between  the  paddle-boxes. 

Having  landed  from  the  Yestal  at  Harwich,  on  the  19th 
Dinner  at  the  of  Jane,  we  returned  to  London  by  rail,  and  I  had  the 

Trinity  House  in 

honor  of  the  pleasure  of  attending  an  annual  dinner  given  at  the  Trinity 

Younger    Breth-  L 

ren.  House,   according  to  custom,   in  honor  of   the  Younger 

Brethren. 

There  were  about  one  hundred  persons  present,  and  the 
th^Lfhfnonse  ver^  complimentary  allusions  made  by  Sir  Frederick  Arrow, 
uniterddstate8the  Deputy  Master  of  the  Trinity  House,  in  the  course  of  the 
after-dinner  speeches,  in  reference  to  the  Light:House  Estab- 
lishment of  the  United  States,  and  toour  Chairman,  Professor 
Henry,  in  particular,  were  received  with  enthusiasm. 

On  the  22d  I  went  down  to  Portsmouth  by  rail,  with  Sir 
Naval  review  Frederick,  to  witness  the  grand  naval  review  at  Spithead  in 

in  honor  of  the ,  ,^1     i        /»  T^        •  «  •   i  ,11 

shah  of  Persia,  honor  of  the  Shah  of  Persia,  which  was  to  take  place  on  the 
23d,  after  which  I  was  to  embark  on  the  Vestal  for  an  in- 
spection of  the  lights  on  the  south  and  southwest  coasts  of 
England. 

Sir  Frederick  was  kind  enough  to  invite  me  to  accompany 
him  on  board  the  Galatea,  a  fine  large  steam-yacht  belonging 
to  the  Trinity  House,  which  with  the  Eoyal  Yacht  Alberta 
formed  the  escort  to  the  Yictoria  and  Albert,  which  carried 
the  Shah,  his  Eoyal  Highness  the  Prince  of  Wales,  and  other 
members  of  the  royal  family  through  the  lines,  so  that  I  had  an 
excellent  opportunity  of  seeing  this  magnificent  pageant, 
which  comprised  nearly  all  the  celebrated  iron-clads  of 
Great  Britain,  including  the  Agincourt,  the  Hercules,  the 
Devastation,  and  eight  others,  and  surpassed  even  the  re- 
view of  Sir  Charles  Napier's  Baltic  fleet  during  the  Crimean 
war,  the  only  one  in  history  comparable  with  it. 

joining  the  On  the  24th  I  left  the  Galatea  and  joined  the  Yestal  to 
accompany  Captain  Webb,  of  the  Elder  Brethren,  on  the  pro- 
posed cruise  of  inspection. 

On  this  journey  we  had  the  pleasure  of  the  society  of  an 
agreeable  guest  of  the  captain,  Colonel  Sim,  of  the  Eoyal 
Engineers,  who  remained  with  us  till  we  left  the  yacht  at  Saint 
Ives,  on  the  west  coast  of  Cornwall. 

Detention  a  t  We  steamed  over  to  Cowes,  on  the  Isle  of  Wight,  where 
we  were  detained  a  day  by  a  severe  storm,  but  the  deten- 
tion afforded  me  an  opportunity  of  inspecting  the  Trinity 
House  depot  in  the  harbor,  the  light-house  of.  Saint  Cath- 
erine on  the  outer  side  of  the  island,  and  a  drive  to  Osborne 
House. 

Trinity  House     The  depot  is  very  complete,  and  is  fitted  up  with  every 
depot  at  cowes.  conveuience  for  the^supply  of  the  lights  of  the  district. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  133 

Tbe  buildings  and  landing-place  are  unusually  fine,  the 
latter  being  used  by  the  Queen  during  her  residence  on  the 
island. 

ST.    CATHERINE. 

This  station  is  on  the  extreme  point  of  the  southern  or    Position, 
sea-face  of  the  Isle  of  Wight,  and  we  reached  it  by  carriage 
from  Cowes,  crossing  the  entire  breadth  of  the  island,  the 
topographical  features  of  which  are  everywhere  beautifully 
diversified. 

The  tower,  which  is  122  feet  high,  and  carries  a  fixed    Tower, 
light  of  the  first  order,  is  octagonal  in  form,  and  is,  as  are 
all  the  buildings  of  the  station,  of  a  pleasing  design,  being 
built  of  stone  in  the  crenelated  style,  and  in  the  most  thor- 
ough manner. 

Unfortunately  there  is  occurring  here  what  I  have  ob-    Gradual  mov- 
served  before  only  on  the  coast  of  California,  i.  e.,  the  entire  suf  face  ^f^tS 
surface  of  the  side  of  the  great  cliff  which  rises  behind  thelai 
light-house  and  the  plateau  on  which  it  stands  are  grad- 
ually moving  toward  the  sea,  sliding  upon  some  stratum 
below,  carrying  the  fine  tower,  which  is  already  slightly  out 
of  the  vertical,  with  it;  and  unless  some  means  are  taken 
to  prevent  further  motion  of  the  tower  much  trouble  is 
anticipated. 

Below  the  main  floor  of  this  tower  is  the  oil-cellar,  a  cir-    oa-ceiiar. 
cular  room,  having  the  one  hundred  gallon  oil-cans  (or  cis- 
terns as  they  are  termed  in  England)  ranged  around  the 
wall. 

There  is  an  opening  in  the  middle  of  the  floor  above  this  Filling  oil- 
cellar  through  which,  when  oil  is  being  delivered  at  the 
station,  is  passed  a  tube  about  4  inches  in  diameter,  which 
is  bent  below  the  arch,  so  that  it  can  be  turned  into  any  of 
the  cans,  while  at  the  upper  end  and  above  the  floor  is  fitted 
a  large  funnel,  into  which  the  oil  is  poured,  so  that  it  is  not 
necessary  to  carry  it  below  the  main  floor  of  the  tower. 
(See  Fig.  13.) 

This  is  a  fog-signal  station,  and  on  the  point  in  front  of   Engine  for  fog- 
the  light-house  is  the  engine-house,  containing  an  Ericsson Blg 
hot-air  engine  of  24-inch  cylinder,  4  horse-power,  and  run- 
ning under  12  pounds  of  pressure. 

The  trumpet  rises  through  the  iron  roof,  and  its  face,    Fog-signai. 
which  is  vertical,  turns  through  the  sea-arc  of  the  hori- 
zon 215°. 

AvS  an  instance  of  the  effect  of  projecting  points  which  Effect  of  pro- 
produce  sound-shadows  that  very  often  interfere  with  the  Jroduf  ing  sound8 
utility  of  fog-signals,  I  will  mention  that  on  the  night  be-8hadowa 


134 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

fore  our  visit  to  Saint  Catherine  a  large  vessel  had  gone 
ashore  in  a  bay  three  miles  to  the  westward,  the  night  being 
foggy  and  an  intervening  point  preventing  the  sound  of  the 
signal  from  covering  that  part  of  the  shore.  There  are 
three  keepers  at  this  station. 

Fig.  13. 


THE  NEEDLES. 

Location  and     This  light-house  is  situated  on  an  island  at  the  western 

characteristics.  ..          „  .,        T  ,         ,,  -rrr    -,  .  -,    •,  -,        r>        i 

extremity  of  the  Isle  of  Wight,  and  has  a  first-order  fixed 
dioptric  apparatus,  producing  two  red  and  two  white  sectors 
of  illumination. 

Red  cuts.  The  following,  from  the  British  light-house  list,  shows 

another  application  of  the  system  of  ared  cuts,"  of  which  I 
have  before  made  mention,  and  of  which  there  are,  as  will 
be  observed,  many  examples  in  the  English  light-houses  : 

"  NEEDLES  LIGHT. — Red  when  bearing  from  N.  W.  J  N. 
(round  northerly)  to  E.  White  from  E.  to  E.  8.  E.  ;  red  from 
E.  S.  E.  (round  southerly]  to  8.  W.  by  W.  ;  and  ivhite  from 
8.  W.  by  W.  to  S.  W.  by  W.  $  W.  The  white  light  shows  in 
the  direction  of  the  Needles  Channel,  its  southern  limit  bearing  JE. 
passes  one  and  a  half  miles  S.  of  Durlston  Head,  and  about  a 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  135 

cable  8.  of  outer  part  of  Bridge  Reef.  Its  northern  limit,  bear- 
ing E.  S.  E.j  passes  two  cables  south  of  Dolphin  Banlc,  and  the 
S.  W.  buoy  of  the  Shingles. 

"The  ray  of  u-hiie  light  between  the  bearings  of  S.  W.  by  W. 
and  S.  W.  by  W.  J  W.  clears  Warden  ledge." 

We  did  not  visit  this  light,  but  as  we  passed  it  early  in 
the  morning  it  shone  brilliantly  and  gave  us  a  good  illus- 
tration of  the  system  of  pointing  out  dangers  by  "red 
cuts." 

THE  BILL  OF  PORTLAND. 

We  passed  in  view  of  these  two  fine  light-houses  on  the 
coast  of  Dorsetshire  without  stopping. 

They  were  built  in  1716,  and  in  1788  the  coal-fires  which  .^ate  of  build- 
burned  on  their  summits  were  extinguished   and  oil  first 
came  into  use. 

They  are  about  five  hundred  yards  apart,  and  form  a  range 
or  lead  between  the  Race  and  Shambles. 

THE  START. 

The  Start  light-house  is  a  bold  headland  on  the  coast  of 
Devonshire,  and  when  I  visited  it  there  were  extensive    Repairs. 
renovations  going  on,  including  the  placing  of  one  of  the 
latest  first-order  lanterns,  of  Mr.  Douglass's  design — 13  feet 
inside  diameter — in  lieu  of  the  old  one. 

The  light  is  revolving,  and  the  difficulty  of  making  this    change  of  iau- 

tern  without  ex- 

change  without  extinguishing  the  light  was  overcome  by  the  gnguWrtng   the 
use  of  a  ship's  revolving  catoptric  apparatus  of  the  same 
interval,  building  the  new  lantern  up  around  it. 

This  lantern  has  diagonal  bars  of  steel  formed  of  two    Diagonal  sash- 
thicknesses  of  J  inch  each,  so  the  bar,  when  finished,  is  3 
inches  by  1  inch. 

The  glass  (J  inch  thick)  is  not  set  in  a  rebate,  but  the    Setting  of  the 
lozenge- shaped  panes  abut  against  each  other  outside  the  s ' 
bars,  and  the  joints  are  covered  by  strips  of  brass  fastened 
by  screw-bolts,  through  the  glass  and  into  the  steel  bars. 
The  cost  of  these  lanterns  is  about  £1,700,  ($8,500.)  Cost  of  lantern. 

There  is  a  lower  light-room,  from  which  a  single  reflector    Lower    light- 
throws  a  fixed  light  over  a  danger  called  "  The  Skerries." 

There  is  a  fog-bell  at  this  station,  weighing  thirty-five 
hundred  pounds,  and  struck  on  the  inside  by  machinery.  It 
strikes  five  hours  without  winding  up  the  weights,  an  opera- 
tion requiring  fifteen  minutes,  during  which  the  striking  is 
interrupted. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Resemblance  to  The  resemblance  of  Start  Point  to  Point  Bonita,  at  the 
entrance  of  the  Golden  Gate  of  San  Francisco,  is  remark- 
able. 

THE  EDDYSTONE. 

view  of  the  On  the  morning  of  the  26th  of  June  we  came  in  sight  of 
the  light-house  which,  more  than  any  other  extant,  is  known 
throughout  the  world  as  a  splendid  proof  of  the  ability  of 
man  to  overcome  the  force  of  the  sea — the  famous  Eddy- 
stone,  which  lies  off  the  coast  of  Devonshire. 

sweii  of  the  sea  There  was  a  heavy  swell  from  the  Atlantic,  and  as  the 
preventsianding.  yesta|  neared  the  light-house  we  were  disappointed  to  see 
the  waves  running  high  up  the  tower,  and  the  keepers'  signal 
from  the  gallery  at  its  summit  that  a  landing  was  impracti- 
cable ]  but  I  was  much  gratified  at  having  even  such  an 
opportunity  of  seeing  this  historical  work. 

Appearance.  Neither  in  height  nor  in  appearance  is  it  the  equal  of 
either  of  the  modern  light  houses  The  Wolf  or  The  Long- 
ships,  off  Land's  End,  which  I  afterward  visited,  yet  I  could 
not  but  feel  a  thrill  of  admiration  as  I  gazed  at  this  grand 
old  tower  which  has  so  successfully  battled  with  the  sea  for 
one  hundred  and  fifteen  years. 

Date  of  build-  The  first  light-house  on  the  Eddystone  was  commenced  in 
t?ouseeonrthe*  Ed-  1G96,  finished  in  1698,  and  was  destroyed  in  a  terrible  storm 
in  1703.  Not  a  vestige  of  the  building  remained,  and  neither 
its  keepers  nor  Henry  Winstauley,  its  builder,  who  had 
wished  to  be  in  his  light-house  "in  the  greatest  storm  that 
ever  blew  under  the  face  of  heaven,"  were  heard  of  after- 
ward. 

Date  of  build-  The  second  light-house  was  built  by  John  Eudyerd.  It 
was  lighted  in  1709,  and  destroyed  by  fire  in  1755. 

Date  of  build-  The  builder  of  the  present  light-house  was  John  Smeaton, 
on?. l  a  who  commenced  the  work  in  1756,  and  finished  it  in  1759. 

Account  of  Of  the  construction  he  has  given  a  most  interesting  nar- 
rative, or,  as  he  styles  it  in  the  dedication  to  his  King,  "  a 
plain  account  of  a  plain  and  simple  building  that  has  never- 
theless been  acknowledged  to  be  in  itself  curious,  difficult,  and 
useful,"  which  clearly  exhibits  the  industry,  perseverance, 
and  genius  of  one  of  the  most  remarkable  of  men.  His 
plan  was  entirely  different  from  those  of  his  predecessors, 
he  having  conceived  the  idea  that  a  light-house  in  a  posi- 
tion like  this,  in  order  to  withstand  the  sea,  must  depend 
upon  its  weight. 

Method  of  join-  He  therefore  built  it  of  stone,  dovetailing  the  joints,  as 
ing  the  stones.  shown  iu  plate  XXI,  so  that  no  stone  can  be  moved  with- 
out displacing  the  others,  and  his  work  has  furnished  a 
model  upon  which  all  rock  light-houses  built  from  Smeaton's 


Plate  lYffl. 


THE     EDDYSTONE     LIGHT-HOUSE. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


137 


time  to  the  present  have  been  constructed,  except  as  regards 
some  of  the  details,  which  have  been  modified  in  some  de- 
gree by  their  respective  engineers. 

The  science  of  illumination,  as  applied  to  the  Eddystone,  po*4Vi£st  u^el" 
was  far  behind  the  science  of  construction,  and  while 
Smeaton  sprang  at  once  from  the  prejudice  of  his  time  to  a 
full  conception  of  the  true  principles  which  should  govern 
the  construction  of  a  work  of  this  character,  it  remained 
lighted  for  many  years  as  at  first,  by  "twenty-four  candles 
burning  at  once.  Jive  ichereof  iceighed  two  pounds.77* 

Reflectors  were  not  introduced  -until  early  in  the  present   Reflectors  used. 
century,  and  in  1845  these  in  turn  gave  way  to  a  second- 
order  Fresuel  lens,  (fixed,)  the  beam  from  which,  with  its    Fresnei  lens. 
Douglass  burner,  is  equal  to  4,650  candles.    This  was  the 
first  catadioptric  apparatus  ever  constructed. 

SAINT  ANTHONY. 

This  is  an  old  station  on  the  coast  of  Cornwall,  standing    Position. 
on  a  rugged  promontory  projecting  into   the  bay  which 
leads  into  the  harbor  of  Falmouth. 

The  tower  is  square,  and  contains  the  dwelling  for  the    Tower. 
principal  keeper  and  his  family,  the  assistant  occupying  a 
cottage  connected  with  the  tower  by  a  covered  way. 

The  apparatus  is  catoptric,  and  is  composed  of  eight  re-    Apparatus. 
Sectors,  one  on  each  face  of  the  revolving  frame. 

There  is  a  bell,  struck  by  machinery,  but  quite  unlike  the 
others  we  had  seen,  and,  indeed,  there  appears  to  be  no 
uniformity  in  the  bell-machinery  of  the  English  service,  as 
many  being  struck  by  the  hammer  on  the  inner  as  on  the 
outer  side. 

A  single  reflector  is  placed  in  the  living-room  of  the  prin- 
cipal keeper,  and  shows  through  a  square  window  a  fixed 
white  light  to  guide  clear  of  some  dangerous  rocks,  called 

4  'The  Manacles." 

PLYMOUTH. 

This  light-house,  which  corresponds  to  the  general  char- 
acter of  "rock"  light-houses,  is  placed  on  the  end  of  the 
fine  breakwater  which  protects  the  harbor  of  Plymouth, 
and  is  one  of  the  most  elaborate  pieces  of  stone-work  I 
have  ever  seen.    The  material  of  which  it  is  built  is  a  beau-    Material  of 
tiful  granite  from  Penrhyn,  in  Wales,  and  on  the  interior  tovver> 
the  immense  expense  of  the  construction  is  shown  by  the 
exquisite  finish,  almost  polish,  of  the  surfaces.    The  floors,    Beauty  of  fin- 
ceilings,  partitions,  and  walls  are  all  of  granite,  and  no  lin-  1S 
ing  of  any  kind  is  used. 


Low  light. 


*  Smeaton's  Narrative  of  the  building  of  the  Eddystone  Light-house. 


138 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Strength  of  the 
structure. 


Arrange  me  n  t 
of  rooms. 


Characteristics 
of  the  light. 


Red  light,  how 
produced. 


Method  adopt- 
ed to  more  sharp- 
ly define  the 
"  cuts." 


This  tower  is  exposed  to  the  heavy  seas  which  roll  over 
the  breakwater,  and  for  a  distance  of  10  feet  from  the  bot- 
tom it  is  a  solid  mass  of  masonry.  Its  entrance  is  through 
a  heavy  gun-metal  door,  sliding  upon  rollers  at  top  and 
bottom. 

The  lower  floor  contains  the  siore-sooms ;  the  second  floor 
the  oil-rooms;  the  third  floor  the  kitchen  and  living-rooms; 
the  fourth  the  bed-room,  and  the  fifth  the  service-room. 
All  the  doors  and  window-frames  are  of  gun-metal. 

A  small  segment  of  a  fifth-order  dioptric  apparatus  in 
the  watch-room  throws  a  beam  of  leading  white  light 
through  a  small  window  upon  a  buoy  and  the  fairway,  the 
beam  being  limited  by  placing  in  front  of  the  lens  a  me- 
tallic case  in  which  there  is  a  narrow  slit  about  2J  inches 
wide. 

The  main  light  shows  white  within  the  anchorage  and  red 
to  seaward. 

The  red  light  is  produced  by  surrounding  the  lamp,  (one 
of  the  second  order,)  except  for  the  small  arc  covering  the 
anchorage,  with  a  red  cylindrical  glass  about  9  inches  in 
diameter. 

To  more  sharply  define  the  "cut"  between  the  red  and 
white  light,  narrow  vertical  strips  of  red  glass  are  placed 
opposite  the  edges  of  the  segments  of  this  cylindrical  glass 
and  outside  the  lens. 

This  mode  of  producing  red  light  by  means  of  a  cylinder 
around  the  lamp  is  different  from  any  I  saw  elsewhere,  and 
is  shown  in  Fig.  14,  in  which  &,  a',  represent  the  red  shade, 
c  the  lamp,  and  a  the  sector  of  white  light. 

Fig.  14. 


Red  Cut,  Plymouth  Breakwater. 

Libraries.  As  before  observed,  the  corporation  of  Trinity  House  fur- 

nishes its  keepers  with  books  by  means  of  circulating  libra- 
ries, and  there  are  also  fixed  libraries  at  the  station.  The 
latter  contains  bibles,  prayer-books,  dictionaries,  religious 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  139 

works,  and  others  of  permanent  interest  or  value.  The  cir- 
culating libraries  are  carried  in  neat,  strong  boxe,«,  about  12 
inches  square  by  18  inches  long,  and  contain  bound  vol- 
umes of  Punch,  illustrated  periodicals,  novels,  and  other 
light  reading.  There  are  from  eight  to  ten  books  in  each 
box  ;  these  boxes,  which  are  numbered  and  charged  to  the 
principal  keeper  of  the  station  where  left,  are  exchanged  on 
the  visits  of  the  supply-vessel. 

The  keepers  are  uniformed  by  the  Trinity  House,  one  suit    uniform  of 
of  clothing  being  supplied  annually.    At  rock  light-houses 
they  are  also  supplied  with  great-coats. 

They  are  required  to  wear  their  uniforms  on  Sundays  and 
holidays,  when  they  go  to  the  villages  or  to  church ;  also 
whenever  any  of  the  officers  of  the  Corporation  visit  the 
station. 

The  keepers  are  a  bright  and  intelligent  class  of  men,  who  ^character    of 
seem  well  instructed  in  their  duties.    They  are  neat,  trim 
in  their  appearance,  and  manifest  pride  in  the  stations. 

Flag-staffs  at  light-stations  are  universal,  and  whenever    Mag  -staffs 
the  light-house  has  a  land-side  the  mast  is  stepped  on  the 
lantern-gallery. 

The  Trinity  House  flag  is  displayed  on  Sundays  and  holi-    Trinity  House 

i  -.       ,  , ,        m   •    -,      flag  displayed. 

days,  and  when  national  vessels  are  passing,  or  the  Trinity 
House  yachts  are  at  the  stations. 

THE    LIZARD. 

This  is  alarge  establishment  consisting  of  two  towers,  con-    Establishment. 
nected  by  a  long  building  occupied  by  the  keepers  and  their 
families,  and  they  also  contain  the  oil-cellars  and  store-rooms 
of  the  station. 

The  towers,  the  focal  planes  of  which  are  229  and  232  er^eigbt  of ' tow" 
feet  respectively  above  the  sea,  were  first  illuminated  by 
coal-fires  on  the  tops  in  1752.     Oil  was  substituted  in  1812,  u  c°al-firc8  firsr 
and  the  original  lanterns  and  first- order  catoptric  apparatus    on  substituted, 
are  still  in  use. 

The  lanterns  are  excessively  heavy,  but  both  they  and  the  ^1^™*   and 
reflectors  are  good  examples  of  the  light-house  engineering 
of  the  beginning  of  this  century.    Although  they  are  sixty- 
two  years  old  and  have  been   subjected  to  the  thorough 
burnishing  which  the  English  light-keepers  certainly  have 
not  failed  to  perform  faithfully  every  day  of  that  long  period, 
the  reflectors  are  to  all  appearances  as  bright  and  service- 
able as  when  new.    Originally,   reflectors  were  made  by    Orifrina]  meth. 
beating  the  silver  into  parabolic  form,  and  they  were  no  °    ° 
doubt  better  than  can  be  obtained  at  the  present  day. 


140  EUEOPEAN    LIGHT-HOUSE    SYSTEMS. 

characteristics  The  lights  are  fixed,  and  the  apparatus  consists  of  nine- 
teen 21-inch  reflectors  in  each  tower,  each  lighted  by  an 
Argand  burner. 

importance  of  Lizard  Point  is  a  bold  headland  on  the  coast  of  Cornwall, 
projecting  far  beyond  the  general  trend  of  the  southwest 
coast  of  England,  and  Captain  Webb  informed  me  that  as  it 
is  the  first  land-fall  of  most  of  the  oversea  commerce  which 
enters  the  English  Channel,  it  is  one  of  the  most  useful  light- 
stations  of  the  kingdom ;  also  that  the  brilliancy  of  its  lights 

Satisfactory  is  often  praised  by  mariners,  and  no  desire  for  a  change  has 
been  expressed,  for  which  reason  the  Trinity  House  does 
not  propose  to  make  any,  certainly  at  present,  though  it  is 
a  rule  that  when  extensive  repairs  are  necessary  at  large 
stations,  catoptric  apparatus,  of  which  there  are  but  few  exam- 
ples remaining,  is  changed  for  dioptric. 

superiority  of     The  English  have  no  doubt  of  the  great  superiority  of  the 

tusptr  a  latter,  and  its  very  great  economy  in  consumption  of  oil,  but 

when  small  areas  are  to  be  lighted,  as  in  case  of  range  or 

leading  lights,  reflectors  are  in  many  instances  used  instead 

Catoptric  appa- 
ratus, when  used,  of  more  expensive  lenses  of  the  smaller  orders. 

Excellent  con-  ^ne  station  was  in  excellent  condition,  and  maintained  by 
dition  of  station,  three  keepers,  the  principal  of  whom  had  been  forty  years 
in  the  service,  being  a  large  portion  of  the  time  at  the  light- 
house at  Gibraltar,  which  belongs  to  the  Corporation  of 
Trinity  House. 

FO  to  There  are  dangerous  reefs  and  rocks  far  out  in  front  of 

ttie  Lizard,  and  it  is  the  intention  to  place  a  fog-gun  here; 
the  necessity  of  some  powerful  signal  is  very  apparent. 

THE  WOLF. 

Position.  Ten  miles  to  the  southwest  of  Laud's  End  is  one  of  the 

latest  achievements  of  modern  light-house  engineering,  The 
Wolf  Eock  light-house,  a  view  of  which  is  shown  in  Plate 
XIX. 

Date  of  build-  It  was  commenced  in  1862,  under  the  direction  of  the 
iug-  father  of  Mr.  James  K  Douglass,  the  present  engineer  of 

the  Trinity  House,  and  finished  by  the  latter  in  1869. 

Exposed  Posi-  The  rock,  which  is  17  feet  above  low  tide,  (the  tide  rising 
ock'  19  feet,)  has  twenty  fathoms  of  water  around  it;  is  exposed 
to  the  full  force  of  the  waves  of  the  Atlantic,  and  was  for 
centuries  the  dread  of  the  mariner;  now  its  very  distance 
from  the  shore  adds  to  its  value  as  a  site  for  a  light-house 
to  guide  into  the  English  Channel ;  but  there  is  probably 
no  position  whose  occupation  has  required  more  skill  and 
perseverance,  or  more  courage  in  overcoming  difficulties  and 
dangers. 


Piate  XIX. 


THE    WOLF     ROCK     LIGHT-HOUSE. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  141 

The  position  of  this  light-house  is  shown  in  Plate  XX,    Chart  showing 
which  is  a  chart  taken  from  Mr.  D  ouglass's  interesting  paper,  p° 
concerning  the  history  and  the  peculiarities  of  construction 
of  this  interesting  work ;  to  the  same  paper  I  am  indebted 
for  many  of  the  data  concerning  it  which  1  have  embodied 
herein. 

In  the  year  1795  a  day -beacon  was  erected  here,  and  at    Day-be  a  con  a 

A.  .  '  placed  on  the  site. 

subsequent  times,  others ;  but  they  were  all  carried  away, 
sometimes  by  the  force  of  the  waves,  at  others  by  the  debris 
of  wrecks  striking  against  them. 

Solid  wrought-iron   shafts  of  different  and  increasing    iron   shafts 
diameters  were,  from  tinje  to  time,  sunk  in  the  rock,  and  the 8U 
difficulties  of  the  site  were  such  that,  during  the  construc- 
tion of  the  last  one,  which  occupied  five  years,  but  302  J  hours 
of  work  could  be  obtained  on  the  rock,  and  the  cost  was 
more  than  £11,000,  ($55,000.) 

The  rock  is  submerged  at  high  water,  and  is  but  little   size  of  rock,  and 
larger  than  the  base  of  the  tower,  which  is  41  feet  8  inches  base  of  the  tower, 
in  diameter,  116  feet  high,  and  solid  from  base  to  a  height 
of  39  feet  or  to  the  door  of  the  light-house.     The  thick- 
ness of  the  walls  at  the  doorway  is  7  feet  9£  inches,  and    mlls- 
at  the  top,  which  is  17  feet  in  diameter,  it  is  2  feet.    The 
shaft  is  a  concave  elliptic  frustum,  the  generating  curve  of 
which  has  a  major  axis  of  236  feet  and  a  minor  axis  of  40 
feet. 

The  stones  are  laid  in  offsets  to  the  level  of  40  feet  above  .  Manner  of  lay- 
ing the  stones. 

the  rock,  with  a  view  of  breaking  the  sea,  and  above  that 
height  the  surface  is  smoothly  cut. 

Each  face-stone  is  dovetailed  vertically  and  horizontally    Dovetailing 
into  the  adjoining  stones,  and  every  stone  is  bolted  to  the 
course  below  it  by  two  2-inch  bolts,  of  yellow  metal  for  the 
exterior,  and  galvanized  steel  for  the  interior  stones. 

The  dovetailing;  was  adopted,  not  only  for  increase  of   Reasons  for 

dovetailing. 

strength,  but  to  prevent  displacement  by  the  sea  during 
construction,  before  the  superincumbent  weight  of  the  ad- 
ditional courses  could  be  obtained,  and  to  protect  the 
cement  mortar  of  the  joints  from  being  washed  out  before 
it  could  be  set. 
Mr.  Douglass  stated  that  the  additional  cost  of  the  dove-  Additional  cost 

of  dovetailing. 

tailing  was  not  more  than  1  per  cent.,  and  that  during  the 
construction  there  were  lost  but  thirty-four  stones,  they  be- 
longing to  an  incomplete  course  which  it  was  impossible  to 
finish  at  the  end  of  the  working-season  before  the  winter  of 
1865. 

On  Plate  XXI  will  be  found  horizontal  sections  through 
the  masonry  of  The  Wolf  and  five  other  rock  light-houses 


142 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


of  the  same  general  character,  viz  :  Eddystone,  Skerry  vore, 
Inch  Cape  or  Bell  Rock,  Minot's  Ledge,  and  Spectacle  Eeef. 

These  sections  are  taken  uniformly  at  10  feet  above  high 
water,  and  are  interesting  as  exhibiting  the  different 
methods  of  arranging  the  dovetail  joints  of  the  stones  to 
prevent  displacement  by  the  sea. 

Number  of  Considering  the  exposure  of  the  rock,  which  may  be  esti- 
mated from  the  fact  tha,t  but  twenty-two  landings  and 
thirty-eight  hours'  work  could  be  had  upon  it  during  the 
first  year  of  the  construction ;  that  the  depot  where  all  the 
stones  were  cut  was  at  Penzance,  seventeen  miles  from  the 
».rock;  that  the  light-house  contains  44,506  cubic  feet  of 
granite,  and  weighs  3,296  tons,  it  is  not  surprising  that  it 
cost  £62,726,  or  more  than  $300,000,  a  cost  which  compares 
favorably  with  that  of  other  structures  of  similar  character. 

I  find  in  Mr.  Douglass's  printed  narrative  of  the  work 
the  following  interesting  table : 


Cubic    feet    of 
granite. 
Weight. 

Cost. 


Comparati 
table  of  costs  of 
seven  rock  light- 
houses. 


Total  cost. 

Cubic  feet. 

Cost  per  cu- 
bic foot. 

Eddystone 

&      s.  d. 
40  000    0  0 

13  343 

£  s.  d. 
2  19  11 

BeUItcck   ..     . 

•     55  619  12  1 

28  530 

1  19    0 

Skerry  vore  

72  200  11  6 

58  580 

1     4    7f 

Bishop 

34  559  18  9 

35  209 

19    7i 

Smalls  

50  124  11  8 

46  386 

1     1    7i 

Hanois 

25  296    0  0 

24  542 

1     0    7i 

Wolf 

62*  726    0  0 

59  070 

113 

Store-room. 


Hoisting  -  d  e  r- 


rick. 


The  first  room  above  the  solid  part  of  the  tower,  (to  which 
access  is  obtained  by  a  strong  ladder  reaching  from  the 
rock  and  bolted  to  the  tower,)  as  well  as  the  next  above,  is 
used  for  stores. 

The  latter  room  has  an  opening  through  the  wall  of  the 
tower,  through  which  a  derrick  can  be  run  out;  by  means 
of  this  and  a  winch  inside  are  hoisted  the  oil  and  other  sup- 
plies of  the  light-house. 

The  next  room  above  is  the  oil-room;  then  come  suc- 
cessively the  kitchen,  the  bed-room,  with  five  recesses  in 
the  walls  for  beds,  and  lastly  the  service  or  watch-room. 

The  dioptric  apparatus  is  of  the  first  order,  manufactured 
by  Chance  Brothers  &  Co.,  of  Birmingham,  and  shows  alter- 
nate red  and  white  flashes  at  intervals  of  thirty  seconds. 
investigation     Previously  to  the  construction  of  the  lens  an  investiga- 
te determine  IMB  tion  was  entered  into  by  Professor  Tyndall,  the  scientific 
Ltefvention3  o^adviser  of  the  Trinity  House,  to  determine  the  loss  of  light 
caused  by  the  rays  passing  through  the  red  glass,  and  it 
was  found  that  for  an  equal  range  of  the  red  and  white 
light  from  the  same  lamp  it  was  necessary  to  make  the  arcs 


Oil-room. 


Apparatus. 


P-ATE 


St Agnes  Revolving  WMteJMfht 

!>«.  Interval  'ofjltusj,  Onr.M~inute 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  143 

of  the  red  and  the  white   sectors  in  the  ratio  of   21  to  0    Ratios  of  areas 

of  red  and  white 

nearly ;  and  this  rule  was  followed  at  The  Wolf,  so  that  its  sectors. 
beams  of  red  and  white  light  have  the  same  value. 

The  lantern  is  of  the  cylindrical  helically  framed  kind,  i-antem. 
and  upon  the  lantern-gallery  is  placed  a  fog-bell,  struck  by  F°s-belL 
means  of  machinery  placed  within  the  pedestal  of  the  lens. 

There  is  but  little  wood  used  in  the  construction  of  the   Gun-metal  used 
interior  of  the  light-house,  and  all  of  the  doors,  the  window-  frames!  &c.d  ° 
frames,  and  storm-shutters  are  of  gun-metal.    I  was  told 
that  bronze  was  habitually  used  for  window-frames  and 
sash-bars  at  rock-stations,  and  oak  for  those  of  shore-stations. 

The  windows  of  the  watch-room  are  arranged,  as  shown    watch-room 

windows. 

in  Plate  VIII,  for  admitting  air  to  support  combustion  in  the 
lamp,  by  means  of  a  valve  in  the  upper  part,  the  current 
passing  over  the  heads  of  the  keepers  and  through  the 
grating  which  forms  the  lantern-floor. 

As  at  other  stations,  I  observed  that  the  floor  of  the  ex-    Floor  Of  ian- 
terior  lantern -gallery,  unlike  ours,  is  made  of  stone  with 
raised  joints,  i.  e.,  the  surfaces  for  about  one-half  an  inch  on 
each  side  of  the  radial  joints  do  not  partake  of  the  inclina- 
tion of  the  general  surface,  but  are  quite  level. 

There  are  four  keepers  belonging  to  the  station,  and  three    Number  of 
of  them  are  constantly  in  the  tower,  while  the  fourth  is  on 
shore  with  his  family. 

The  stated  term  of  service  on  duty  on  the  rock  is  one    Term  of  service 
month,  but  it  sometimes  happens  that  eight  weeks  or  more  before  relieve(1 
elapse  before  a  sea  can  be  found  sufficiently  quiet  to  make 
a  landing  practicable. 

As  before  stated,  the  rock  upon  which  the  light-house 
stands  is  submerged  at  high  water,  and  the  winch,  mast, 
and  boom  of  the  derrick  used  for  landing  the  keepers, 
visitors,  and  provisions  are,  when  not  in  use,  laid  into  deep 
troughs  or  recesses  in  the  stone  and  strongly  fastened  down 
to  protect  them  from  the  sea. 

It  was  a  comparatively  calm  day  when  I  went  to  The    Method  of  lami- 
Wolf,  and  I  was  fortunate  in  being" able  to  land  upon  the^fkupon  the 
rock  ;  but  it  is  an  undertaking  attended  with  a  good  deal  of 
danger,  and  many  trials  and  much  delay  were  experienced 
before  we  were  successful. 

The  landing-boat,  which  is  well  adapted  for~the  purpose,    Landing-bout. 
is  built  diagonally  of  two  thicknesses  of  elm-plank,  without 
timbers  or  floor,  and  is  provided  in  the  bow  with  a  landing- 
deck  and  stake. 

This  deck  and  the  forward  part  of  the  gunwale  are  cov- 
ered with  rough  rope-matting  to  prevent  slipping  in  jump- 
ing into  or  from  the  boat,  which  is  warped  in  by  means  of  a 


144  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

line  made  fast  to  a  buoy  astern  and  two  lines  from  the  bows, 
the  latter  of  which  are  managed  by  the  men  on  the  rock. 

The  person  who  is  to  land  is  provided  with  a  cork  life- 
belt, and  stands  on  the  landing-deck  forward,  holding  the 
stout  mast  or  stake  with  both  hands,  and  when  the  proper 
instant  arrives,  of  which  he  is  warned  by  the  coxswain,  who 
watches  the  waves  and  manages  the  line  astern,  he  seizes 
the  rope  which  is  lowered  from  the  end  of  the  derrick-boom, 
places  one  foot  in  the  loop  at  the  end,  and  is  quickly  hauled 
up  by  the  men  at  the  winch  on  the  rock. 

Danger  attend.  Lauding  by  the  mode  I  have  described  is  comparatively 
safe,  but  is  often  impracticable,  and  sometimes  when  the 
keepers  are  relieved  they  are  pulled  through  the  surf  into 
the  boat  when  it  cannot  get  near  enough  to  the  rock  to  per- 
mit of  their  being  dropped  into  it. 

Thie  light-house  is  one  of  the  most  striking  examples  of 
rock  light-house  engineering  for  which  Smeaton's  Eddystone 
has  furnished  the  model. 

More  of  this     There  are  now  several  of  this  type  in  the  various  countries 
houses  °fn  Great  of  the  globe,  but  Great  Britain  possesses  more  than  any 

Britain  than  else-     .. 
where.  Oilier. 

Notable  in-     In  the  United  States  we  have  notably  two  ;  one  built  by 

united  states. 1  General  Alexander,  of  the  United   States  Engineers,   on 

Miuot's  Ledge,  off  the  coast  of  Massachusetts,  where  the 

rock  is  exposed  to  the  full  force  of  the  Atlantic,  and  is  only 

uncovered  at  extreme  low  water ;  the  other  proposed  by 

General  Eaynolds  and  built  by  General  Poe,  both  of  the 

United  States  Engineers,  and  the  latter  now  a  member  of 

the  Light-House  Board,  on  Spectacle  Eeef,  in  Lake  Huron, 

the  site  of  which  is  10  feet  below  the  surface. 

spectacle  Eeef,     The  latter,  however,  was  quite  a  different  problem  from 

difficulties  met  in  ...  , 

building.  any  of  the  others  in  that  the  structure  was  to  withstand 

the  immense  fields  of  moving  ice  by  which  it  is  assailed  in 
the  spring. 

I  regret  that  I  could  not  visit  the  other  rock  light-houses 
of  England,  or  the  Skerry  vore  and  Bell  Rock,  the  latter  of 
which  have  given  so  enviable  a  reputation  to  the  Stevensous, 
the  distinguished  family  of  Scottish  light-house  engineers. 

THE  RUNDLESTONE  BELL-BUOY. 

The  bell-buoy  which  marks  the  Kundlestone,  off  the  point 

of  Laud'sEnd,is  10  feet  in  diameter  at  the  water-line,  moored 

Moorings.        with  45  fathoms  of  1  J-inch  chain  and  a  30-cwt.  sinker,  which 

is  backed  with  30  fathoms  of  IJ-iuch  chain,  and  a  second 

sinker  of  the  same  weight. 


d 

m 


o 

7) 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  145 

The  bell  weighs  3  cwt.  This  is  a  water-ballast  buoy,  and 
is  shown  in  Fig.  15,  in  which  a  is  the  outer  water-tight 
compartment;  &,  the  inner  water-tight  compartment;  d,  d, 
the  India-rubber  springs. 

Fig.  15. 


Rundlestone  Bell-buoy. 
THE   SEVEN  STONES  LIGHT-SHIP. 

This  vessel,  which  marks  the  dangerous  shoal  of  rocks  in-    Position. 
dicated  by  its  name,  lies  about  twenty  miles  to  the  westward 
of  Land's  End,  or  about  midway  between  it  and  Saint  Agnes 
(Scilly  Islands)  light,  in  what  is  probably  one  of  the  most 
exposed  positions  in  the  world  for  a  light-ship. 

It  is  one  of  the  latest  constructions,  and  has  been  on  the    Age. 
station  about  two  years. 

It  has  two  inasts,  besides  the  mast  for  a  jigger  or  miz-    Masts  ami  ap 
zen,  which  is  stepped  on  the  taffrail.    The  former  carry  two 
fixed  catoptric  lights,  28  and  20  feet  above  the  sea. 

A  fog-trumpet,  of  Professor  Holmes's  patent,  shown  in    Fog-trumpet. 
Plate  XXII,  is  operated  by  a  hot-air  engine,  the  cylinder  of 
which  is  24  inches  in  diameter. 

The  engine  is  placed  between-decks,  amidships,  and  the    Engine  and 
horn  between  the  masts  on  deck. 

I  should  think  the  utility  of  the  signal  much  impaired  by    Length  of  time 
the  length  of  time  required  to  generate  sufficient  pressure 


to  operate  it,  which  I  was  informed  is  an  hour  and  three-  ' 

quarters. 

This  is  a  serious  objection  in  any  fog-signal,  since  the  fires 
are  ordinarily  not  started  till  the  fog  comes  on,  and  in  the 
S.  Ex.  54  -  10 


146  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

long  interval  before  the  warning  is  given  serions  accidents 
are  liable  to  occur. 

"Heaters"  used     For  our  signals  operated  by  steam,  we  frequently  provide 
s  "  heaters,"  by  which,  with  a  very  small  expenditure  of  fuel^ 
the  water  in  the  boiler  is  kept  hot,  so  that  when  the  signal 
is  required,  a  quick  fire  will  raise  the  pressure  to  the  required 
point  in  a  few  minutes. 

can     The  fog-signal  on'the  Seven  Stones  can  be  operated  by 
lSnd.perated  by  hand,  by  means  of  a  pair  of  air-pumps  on  deck,  in  case  of 
accident  to  the  hot-air  engine,  or  when  waiting  for  the  re- 
quired pressure,  but  it  is  extremely  hard  work  for  the  sea- 
men, and  I  fancy  the  signal  may  not  be  satisfactorily  sounded 
at  such  times. 
signal-  gun     There  is  also  a  signal-gun  on  deck  which  is  fired  when  a 

fired  when    ves-  ,  .  ,  .          .  •  ,       n 

are    seen  vessel  is  seen  standing  into  danger. 

The  measurement  of  the  Seven  Stones  is  188  tons.     It 


crew- 


moored  in  41  fathoms  of  water  by  200  fathoms  of  1J- 
inch  chain  to  a  mushroom  anchor  weighing  40  cwt.  Three 
hundred  and  fifteen  fathoms  of  chain  can  be  run  out  when 
necessary. 

Crew<  This  light-ship  carries  a  crew  of  fifteen  men  besides  the 

master  and  mate  ;  one  of  the  latter  and  five  of  the  seamen 

uniforms  ofare  constantly  on  shore  with  their  families.  They  are  all 
uniformed,  and  the  name  of  the  vessel  is  marked  upon  their 
hats  and  shirts.  This  rule  applies  to  the  crews  of  all  the 
light-ships  of  England,  and  to  those  of  the  yachts  or  tenders 
belonging  to  the  Trinity  House. 

THE  LONGSHIPS. 

Location.  The  Longships  is  the  name  of  some  rocks  about  a  mile 

and  a  quarter  to  the  westward  of  Land's  End,  on  the  largest 
of  which  is  the  new  first-order  light-house  of  that  name, 
which,  at  the  time  of  my  visit,  was  on  the  point  of  coaiple- 
tion. 

Rough    seas     As  at  The  Wolf,  the  sea  is  generally  rough  at  The  Long- 

prevalent.          ships,  and  when  we  approached  it  on  our  return  from  the 

Seven  Stones  light-ship  to  Penzance,  we  found  it  impossible 

to  land.    The  following  day,  however,  we  made  another 

attempt,  and  were  successful. 

Form  of  rock.  The  rock  on  which  the  tower  is  built  is  conical  in  form, 
and  rises  about  60  feet  above  the  sea  ;  and  the  tower,  which 
is  precisely  like  that  at  The  Wolf,  is  placed  on  a  ledge 
in  front,  about  20  feet  above  the  sea.  The  rock  in  the  rear 
was  being  blasted  down  to  the  level  of  the  top  of  the  .solid 
part  of  the  tower,  at  which  is  the  door  or  entrance. 


HOLMES'S  FOG-HORN  APPARATUS.    PLATE 


XXII. 


ft.  (bch  between>Hanc&Iltm]ps. 


a.  Cratik. 
".  Gem  tifctiria  Root. 
fc. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  147 

Mr.  Michael  Beazeiey,  the  resident  engineer  in  charge  of   Mr.  Beazeiey, 
the  construction  of  The  Longships,  was  also  in  charge  of  The  eu 
Wolf  light-house,  and  I  am  much  indebted  to  him  for  kind 
attentions  on  the  occasion  of  my  visits  to  these  stations,  and 
for  information  in  regard  to  the  works. 

The  courses  of  stone  at  Longships  were  dovetailed,  as  atbu^(g*hoa    of 
The  Wolf,  but  as  the  rock  which  was  blasted  away  for  the 
site  for  the  tower,  was  an  extremely  hards  late,  a  "core"  of 
it  was  left  in  the  interior  to  a  considerable  height. 

These  courses,  to  the  height  of  the  solid  part  of  the  tower,    Thickness   ot 

7  the  stone-courses. 

were  2  feet  in  thickness,  and  above  that  height,  1  foot  6 
inches. 

Quick-setting  cement  was  used  for  setting  the .  lower    Cement  used- 
courses,  and  strong  muriatic  acid  for  removing  the  sea- weed 
from  the  rock,  though  Mr.  Beazeiey  stated  that  lime  is  better 
for  this  purpose,  if  at  least  two  hours  can  be  had  before  it  is 
covered  by  the  tide. 

The  focal  plane  of  Longships  light-house  is  110  feet  above  o^al  Pbne  of 
the  sea. 

The  handsome  new  lantern  was  in  place,  but  the  lens  was  Deflectors    in 
not  set,  and  nineteen  reflectors  were  ranged  temporarily 
around  the  inside  of  the  lantern  to  cover  the  proper  arc  of 
the  horizon. 

As  at  nearly  every  light-house  which  I  visited  on  the  coast    Red  cuts. 
of  England,  there  are  outlying  dangers  marked  by  "  red  cuts." 
(See  Plate  XX.) 

At  Longships  these  dangers  are  on  one  hand  "The  Bri-  gangers  mark- 
sons"  rocks,  and  on  the  other  "  The  Bundlestone,"  each  about 
six  miles  from  the  light-house,  and  being  well  out  from  the 
land,  they  were  for  many  years  the  terror  of  navigators. 

By  the  system  of  marking  out  these  dangers  by  means  of 
red  light,  they  can,  however,  be  avoided  with  absolute  cer- 
tainty in  all  weathers,  except  when  the  light  is  obscured  by 
fog. 

As  an  evidence  of  the  force  of  the  waves  off  Land's  End, 


it  may  be  mentioned  that  before  the  commencement  of  the  °fl 
new  tower  at  The  Loogships,  a  granite  light-house,  the  focal 
plane  of  which  was  79  feet  above  high  water,  occupied  the 
site ;  but  owing  to  the  terrific  seas  to  which  it  was  exposed, 
the  lantern  was  so  often  under  water  in  stormy  weather  that 
the  character  of  the  light  could  not  with  certainty  be  deter- 
mined by  mariners,  and  the  erection  of  a  higher  tower 
became  necessary. 


148  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

GODREVY. 

This  light-house  is  on  a  rock  off  the  west  coast  of  Corn- 
wall, and  about  twenty  miles  to  the  northward  of  The  Long- 
ships. 

Between  this  rock  and  the  mainland  is  a  smaller  rock,  on 

Manner  of  land-  which  the  landing  is  effected.    A  wire  rope  is  stretched 

from  one  rock  to  the  other,  and  a  basket  suspended  from  it, 

is  run  over  the  rough  water  intervening,  and  by  this  means 

the  keepers  and  stores  are  carried  to  the  station. 

When  the  Vestal  approached  the  rock  the  keepers  sig- 
naled that  a  landing  was  impracticable,  and  we  steamed 
away  without  visiting  this  interesting  station,  much  to  my 
regret. 

"  The  stonee."  A  mile  and  a  quarter  outside  of  Godrevy  are  some  sub- 
merged rocks  called  "  The  Stones,"  a  source  of  great  dan- 
ger to  the  mariner.  They  are  unmarked  except  by  a  buoy, 
but  are  covered  at  night  by  a  beam  of  red  light  from  God- 
revy light-house.  (See  Plate  XX.) 

intention  of  As  an  evidence  of  the  intention  of  the  Trinity  House  to 
p/acet^c  light  on  serve  the  best  interests  of  commerce,  Captain  Webb  men- 
tioned that  before  the  light-house  was  built,  the  Corporation 
proposed  to  place  the  light  upon  one  of  "  The  Stones,"  but 
was  overruled  by  the  Board  of  Trade.  The  expense  of  the 
proposed  structure  was  but  a  few  thousand  pounds  more 
than  the  cost  of  the  actual  light-house,  and  the  latter  has 
the  same  expense  of  maintenance  and  the  same  dangers  in 
landing  supplies  of  oil,  &c.,  which  the  former  would  have 
had,  while  the  very  important  advantage  of  marking  "The 
Stones"  is  not  gained. 

"THE  STONES"  BUOY,  OFF  GODREVY. 

This  buoy  is  an  "  egg-bottom,"  water-ballasting,  13  feet 
Moorings.       loug,  moored  in  60  feet  of  water  with  45  fathoms  of  IJ-inch 
chain  and  a  30-cwt.  sinker,  which  is  "backed"  by  30  fath- 
oms of  IJ-inch  chain  and  another  sinker  of  30  cwt. 

Although  this  is  probably  one  of  the  most  exposed  places 
around  Great  Britain,  the  moorings  of  this  buoy  are  so 
excellent  that  it  has  not  been  adrift  in  three  years. 

After  leaving  Godrevy  we  landed  at  Saint  Ives,  on  the 
doneturnt°*Lon"west  coast  of  Cornwall,  and  went  up  to  London  by  rail, 
arriving  there  on  the  1st  of  July.  I  cannot  conclude  the 
notes  on  my  journey  on  the  southwest  coast  of  England 
without  expressing  my  sincere  thanks  to  Captain  Webb  for 
his  kindness  and  his  constant  efforts  to  make  the  cruise 
instructive  and  interesting  for  me,  and  for  the  many  polite 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  149 

attentions  which  I  received  from  him,  from,  the  time  I  first 
arrived  in  London  till  my  departure  for  America. 

On  the  2d  of  July  I  attended  the  annual  dinner  at  the 
Trinity  House,  which  takes  place  on  Trinity  Monday,  at  House. 
which  were  present  His  Royal  Highness  the  Princeof  Wales, 
the  Czarowitch  (eldest  son  of  the  Czar)  of  Russia,  the 
Dukes  of  Argyll  and  Richmond,  and  others  of  the  nobility, 
the  Queen's  Ministers,  and  other  distinguished  personages. 

His  Royal  Highness  the  Duke  of  Edinburgh,  Master  of 
the  Trinity  House,  presided,  and  during  the  evening  I  had 
the  distinguished  honor  of  being  presented  by  him  to  His 
Royal  Highness  the  Prince  of  Wales.  They  both  kindly 
referred,  as  the  former  had  done  before  (as  I  have  men- 
tioned) at  the  dinner  of  the  Lord  Mayor,  to  the  satisfaction 
which  Sir  Frederick  Arrow  and  Captain  Webb,  of  the  Elder 
Brethren,  had  expressed  in  regard  to  their  visit  to  the 
United  States  and  inspection  of  some  of  our  light-houses. 

Before  proceeding  to  Ireland  and  Scotland  I  visited  the 
Continent,  but  I  will  here  continue  my  account  of  the 
British  lights  in  the  order  in  which  I  visited  them  after  my 
return. 

HOLYHEAD. 

Leaving  London  by  train  on  the  14th  of  August,  I  arrived 
at  Holyhead,  on  the  Island  of  Anglesea,  the  following  day, 
where  I  met,  by  appointment,  Mr.  Douglass,  the  engineer  of 
Trinity  House,  and  had  the  pleasure  of  inspecting  with  him 
the  Trinity  House  light-stations  on  the  island. 

The  great  breakwater  for  the  protection  of  the  harbor  of   Breakwater  to 
refuge  at  Holyhead,  together  with  the  light-house  at  its  Eor  of  refuge. ai 
outer  end,  had  just  been  completed;  the  latter,  although 
quite  finished,  was  not  to  be  lighted  until  a  few  days  later, 
when  there  was  to  be  a  grand  demonstration  to  celebrate 
the  completion  of  the  harbor  works,  at  which  the  Prince  of 
Wales  and  several  members  of  the  government  were  to  be 
present.    The  light-house,  which  was  built  from  designs    Light-house. 
approved  by  the  Trinity  House,  by  Mr.  Hawkshaw,  the  dis- 
tinguished engineer  in  charge  of  the  breakwater,  at  the  ex- 
pense of  the  fund  appropriated  for  the  latter,  is  a  handsome 
tower  of  granite  surmounted  by  a  flashing  lens  of  the  third    Lens 
order,  made  by  Chance  Brothers.    Outside  the  parapet  of 
the  tower  is  placed  a  fog-bell,  rung  by  machinery,  which,    Fog-beii. 
together  with  the  usual  revolving  machinery,  is  contained 
within  the  pedestal  of  the  lens.    The  latter  revolves  upon 
conical  wheels,  the  outer  bearing-surfaces  of  which  yre  flat    Fiat  wheels 

used  for   revolv- 

and  not  beveled  as  in  the  French  system  and  our  own.  ing  machinery. 


150 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


amp 


Mr.  Douglass  stated  that  wheels  of  the  latter  kind  wear 
into  the  rail  rough  channels,  which  increase  the  friction  and 
interfere  with  the  regularity  of  motion,  which  is  essential  in 
weigbtsof  the  revolving  machinery  of  light-houses.  The  lamp,  a  "mod- 
erator" of  Chance's  manufacture,  is  like  our  own,  except 
that  the  weights  are  hung  underneath  the  cylinder  or  reser- 
voir, and  are  connected  with  the  plunger  by  means  of  exte- 
rior rods. 

The  plain  pulleys  and  rods  formerly  used  for  revolving  and 
fog-bell  machinery  have  been  replaced  by  chain- wheels  and 
chains  which  are  much  more  durable  and  reliable. 

Fig.  16. 


Lamp  of  single 
and  double  pow- 
er. 


Lamp  of  Single  and  Double  Power. 

The  burner,  shown  in  Fig.  16,  contains  all  the  recent  im- 
provements, one  of  which  gives  to  the  lamp  its  name  of  the 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  151 

"  lamp  of  single  and  double  power."    In  the  figure  a  a  is  the    Explanation  of 
focal  plane;  1)  &,  the  level  of  the  mineral-oil;  c  c,  the  overflow- fij 
holes,  eight  in  number,  and  three-sixteenths  of  an  inch  in 
diameter;  d,  the  interior,  and  e  the  exterior  deflector.    The 
adjustable  chimney,  the  perforated  button,  and  the  conical 
tips  to  the  burners  are  also  shown. 

Between  the  exterior  deflector  or  jacket,  and  the  chimney, 
there  is  an  air-space,  open  at  the  bottom,  through  which  a 
draught  of  cold  air  passes  and  keeps  the  base  of  the  chimney 
so. cool  that  it  can  be  removed  by  the  naked  hand,  as  I 
found  by  experiment,  without  the  use  of  the  tongs  usually 
required.  These  burners  have  three  wicks,  the  exterior 
2|,  the  middle  If,  and  the  interior  J  of  an  inch  in  diameter. 

By  a  simple  movement  the  inner  wick  can  be  lowered 
into  the  burner  and  extinguished,  or  raised  and  lighted. 
This  and  the  change  of  the  perforated  buttons  require  but    Power  of  ad- 
an  instant,  and  the  result  is,  that  the  flame  and  the  amount imi^onsumption 
of  oil  consumed  can  be  exactly  adjusted  to  the  quantity  of of 
light  required.* 

In  fair  weather  only  the  outer  and  middle  wicks  are 
burned,  but  when  fog  or  thick  weather  comes  on,  the  per- 
forated button  is  changed,  and  the  inner  wick  is  raised  and 
lighted. 

This  is  of  great  importance  in  the  economy  of  light-house    Economyoftho 
illumination,  and  the  English  have  been,  as  far  as  I  am burner- 
aware,  the  first  to  attempt  to  vary  the  power  of  oil-lights; 
a  result  which  has  been  effected,  as  I  have  before  stated,  in 
both  the  gas  and  the  electric  lights. 

Photometric  experiments  have  shown  that  the  flame  of   p0wer  of  the 
the  outer  two  wicks  is  equal  to  146  candles,  and  the  lightiuginne™ckflamc- 
of  the  small  interior  wick  raises  the  power  to  208  candles, 
showing  that,  though  the  inner  wick  has  but  19  per  cent,  of 
the  total  burning- surface,  it  yields  30  percent,  of  the  entire 
amount  of  light,  an  amount  very  much  in  excess  of  its 
power  when  burning  alone ;  but  it  must  be  considered  that 
the  circumstances  of  combustion  are  much  more  favorable 
when  the  wick  burns  inside  the  larger  flames. 

The  lantern  at  Holyhead  is  of  the  latest  kind.     The  sash-    Lantern   with 
bars  run  diagonally  from  top  to  bottom,  and  the  panes 
glass  are  of  a  lozenge  shape,  cast  in  cylindrical  form,  cor- drical  slas8- 
responding  to  the  diameter  of  the  lantern.     With  regard  to 
the  diagonal  sash-bars,  Mr.  Douglass  stated  that  Faraday, 
the  predecessor  of  Professor  Tyndall  in  the  oflice  of  scientific 
adviser  of  Trinity  House,  found  that  the  vertical   bars,    Obstruction  of 
which  were  at  one  time  used,  obstructed  at  least  48  per  ight  by  vertical 
cent,  of  the  light  in  certain  directions,  whereas  with  diag- 


152  EUROPEAN   LIGHT  HOUSE    SYSTEMS. 

oiial  bars  the  shadow  was  lost  at  a  distance  of  less  than  a 
hundred  feet.  In  discussing  this  matter  Faraday  consid- 
ered that  the  rays  of  light  issuing  from  the  lens  in  any  di- 
rection, form  at  the  exterior  surface,  a  beam,  a  vertical  sec- 
tion of  which  is  a  column  of  light  of  the  height  of  the  lens ; 
that  with  diagonal  bars  the  beam  from  this  column  of  light 
intersects  them  in  points,  the  shadow  of  which,  the  beam 
being  broader  than  the  sash-bars,  is  terminated  not  far  out- 
side the  la'ntern,  while  with  vertical  bars  the  best  part  of 
the  beam  is  partially  obstructed,  and  a  vertical  shadow  is 
thrown  upon  the  sea. 

Extract    from     The  following  extract  from  a  report  by  Professor  Tyndall 
° '  of  experiments  with  gas  and  oil  burners  at  Howth  Baily 
light-house,  Dublin  Bay,  confirms  this  view: 

"  I  did  not,  however,  think  it  safe  to  limit  myself  to  this 
particular  point  of  observation,  and  to  meet  my  wishes,  Cap- 
tain Roberts  was  good  enough  to  engage  a  steamer,  which 
enabled  me  to  proceed  down  the  river  and  to  pass  across  it 
from  side  to  side  between  the  North  Wall  and  the  South 
Wall,  thus  varying  the  points  of  observation. 

ult  soon  became  manifest  that  the  oil-flame  at  Howth  Baily 
varied  in  intensity  with  our  position,  and  that  the  direction 
of  minimum  intensity  corresponded  almost  exactly  with  that 
in  which  our  observations  had  been  made  on  the  previous 
evening  from  the  North  Wall. 

"  No  safe  conclusion,  therefore,  could  be  drawn  from  the 
observations  made  on  the  evening  of  the  7th,  for  it  was 
manifest  that  some  cause  existed  which  prevented  the  oil- 
lamp  from  displaying  its  full  power  in  the  direction  of  the 
North  Wall,  thus  giving  the  gas  a  relative  superiority,  which 
in  reality  it  did  not  possess. 

"  It  is  to  be  borne  in  mind  that  the  oil-lamp  in  these  ex- 
periments was  placed  in  the  first- order  dioptric  apparatus 
of  the  light-house,  the  apparatus  being,  as  usual,  surrounded 
by  its  glazed  lantern.  The  gas-flame,  on  the  contrary,  was 
placed  in  a  temporary  hut  at  some  distance  below  the  lan- 
tern. A  refracting- pan  el,  similar  in  all  respects  to  those  of 
the  dioptric  apparatus,  was  placed  at  the  proper  distance  in 
front  of  the  gas-flame,  and  to  make  the  conditions  alike,  the 
upper  and  lower  reflecting-prisms  of  the  apparatus  were 
shut  off.  It  was,  therefore,  the  lights  transmitted  through 
the  two  lenticular  belts  that  were  compared  together. 

"In  company  with  Captain  Roberts,  I  again  visited 
Howth  Baily  on  Wednesday,  the  9th. 

"  We  were  preceded  by  Captain  Hawes  and  Mr.  Wig- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  153 

ham,  who  were  instructed  to  examine  with  all  care  whether 
any  obstruction  was  offered  by  the  lantern  to  the  passage  of 
the  light  toward  our  station  on  the  Xorth  Wall. 

ult  was  soon  found  that  one  of  the  vertical  sashes  of  the 
lantern  was  directly  interposed  between  the  light  and  our  point 
of  observation,  and  that  to  this  obstruction  the  enormous  appar- 
ent superiority  of  the  gas  flame  over  the  oil,  manifested  on  the 
evening  of  the  7th,  was  to  be  ascribed. 

"  Since  my  return  to  London,  Captain  Roberts,  at  my  re- 
quest, placed  the  gas-flame  in  the  dioptric  apparatus  and 
the  oil-flame  in  the  hut  below.  From  the  North  Wall  the 
oil-flame  was  the"  brightest,  thus  affording  additional  evi- 
dence, if  any  were  needed,  as  to  the  influence  of  the  obstruc- 
tion offered  by  the  sash  of  the  lantern." 

M.  Quinette  de  Eochemont,  engineer  des  Fonts  et  Chaussees,  Te^™f  Mfrotg 
who  is  charged  with  the  supervision  of  the  French  lights  Rochemont. 
north  of  the  Lower  Seine,  in  his  "  Note  sur  les  Phares  Elec- 
triques  de  la  Heve?  referring  to  experimental  comparisons 
between  the  electric  lights  at  La  Heve  and  the  oil-lights  at 
Honfleur,  Fatouville,  and  Ver,  remarks  as  follows : 

"  The  observations  at  Fatouville  show  an  anomaly,  but 
this  is  easily  explained,  as  it  was  in  consequence  of  one  of 
the  uprights  of  the  lantern  of  the  northern  (oil)  light-house 
being  placed  in  the  direction  of  Honfleur.  and  thus  obscur- 
ing a  considerable  part  of  the  light  from  the  apparatus." 

This    matter    is  still  further  illustrated  by  Fig.  17,  in    English    and 

American       Ian 

which  a  section  of  the  beam  is  shown,  partially  eclipsed  in  terns. 
one  case  by  a  vertical  sash-bar  of  the  lantern  a,  constructed 
on  the  American  and  French  plan,  and  in  the  other  crossed 
by  the  diagonal  sea-bars  of  an  English  lantern,  &,  the  width 
of  the  beams  being  drawn  the  same  in  both  cases. 

In  1873,  the  engineer  of  our  seventh  light-house  dis-    complaints 

made  of  the  light 

tnct  reported  to  me  that  grave  complaints  were  made  of  at  Key  west  due 

.  to  shadows   cast 

the  light  at  Key  TV  est,  it  having  been  reported  by  mariners  by  broad  sash- 
to  have  been  extinguished  on  several  occasions. 

On  investigation  it  was  found  that  such  large  shadows  were 
cast  by  the  great  sash-bars  of  the  old-fashioned  lantern 
of  the  light-house  that  vessels  were  sometimes  in  shadow 
for  a  long  time,  and  to  this  cause,  and  not  to  the  want  of 
vigilance  on  the  part  of  the  keeper,  were  the  above  reports 
due.  This  old  lantern  has  since  been  replaced  by  one  of  the 
new  model,  in  which  the  width  of  the  sash-bars  is  very  much 
less  than  in  the  old. 

I  have  been  thus  particular  in  referring  to  the  subject  of  ob-  Error  of  the 
struction  by  vertical  sash-bars  in  light-house  lanterns,  since  oV^sYn?  vSS 
in  our  service  vertical-barred  lanterns  have  always  been barrcd  lanterus- 


154 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


used,  and  I  believe  it  to  be  a  very  serious  error  into  which  we 
have  been  led  by  an  improper  consideration  of  the  matter. 

cylindrical ian-  Mr.  Douglass  stated  that  he  had  found  by  experiment 
that  cylindrical  lantern-glass  is  68  per  cent,  stronger  than 
plate-glass,  an  important  consideration  to  us,  particularly 
with  regard  to  our  southern  coast,  where  our  lantern -glass, 

•oi?£Seib  ^  tea8  Chough  one-half  an  inch  in  thickness,  is  frequently  broken 
by  sea-fowl,  which,  blinded  by  the  light,  fly  against  the  lan- 
tern, damaging  not  only  that,  but  the  lenticular  apparatus, 
to  such  a  degree  that  we  have  been  obliged  to  cover  the 
entire  face  of  lanterns  with  netting,  necessarily  of  such 
strength  and  size  of  wire  as  to  impair  the  value  of  the  light. 

Fig.  17. 


fowl. 


Low  parapet 
used  on  English 
towers. 


Ventilation. 


American  aud  English  Lanterns. 

With  further  reference  to  the  English  lantern,  I  will  remark 
that  the  substitution  of  the  low  parapet  in  place  of  the  high 
one  used  by  the  French  and  ourselves  does  not  seem  to  me  to 
be  an  improvement.  The  former  necessitates  the  use  of  a  step- 
ladder  when  cleaning  the  lenticular  apparatus,  and  the  door 
for  reaching  the  outer  gallery  is  necessarily  low  and  incon- 
venient. The  English  provision  for  egress  of  heated  air 
and  smoke  is  not  as  good  as  our  own,  and  the  arrangement 
for  turning  the  cowl  with  the  wind  I  should  think  liable  to 
become  obstructed  by  soot  and  dust.  I  have  the  same 
opinion  with  regard  to  the  manner  of  providing  fresh  air  to 
support  combustion  in  the  lamp.  The  English  admit  this 


"EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


155 


into  the  watch-room  and  thence  through  the  grating  of  the 
lantern-floor.  (See  Plates  VII  and  VIII.)  It  is  true  that  the 
tops  of  the  ventilating  windows  in  the  watch -room  are  above 
the  heads  of  keepers  on  watch,  but  in  our  cold  latitudes  this 
would  be  quite  inadmissible,  and  in  no  case  do  I  perceive  the 
English  mode  to  be  in  any  way  superior  to  ours  of  admitting 
the  exterior  air  directly  into  the  lower  part  of  the  lantern. 
The  excess  of  2  feet  in  the  diameter  of  their  lanterns  Superior  size  ot 

lantern  used   by 

over  our  own  I  think  unnecessary,  as  we  have  found  12  feet  the  English  not 
to  be  quite  sufficient,  affording  abundance  of  space  between  vantage  to  com. 

.  .,  ~  ...    pen  sate    for    the 

the  lens  and  the  lantern -sides.    On  our  eastern  coast,  with  consequent    in- 

M       i  •    ,  ,-,  n    CL    f>  -IT    creased  cost  of 

our  necessarily  high  towers,  the  expense  of  2  feet  addi-  towers, 
tional  to  the  diameter  of  lanterns  and  towers  is  much  greater 
than  in  England,  where  the  towers  are  ordinarily  on  elevated 
sites,  requiring  but  small  elevations  of  the  lights. 

NORTH  STACK. 

This  fog-signal  station  is  about  four  miles  south  of  Holy- 
Fig.  18. 


Wind-guard. 

head  Harbor,  on  the  east  side  of  Saint  George's  Channel.  The 


156  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Fog-signal.  signals,  which  are  in  charge  of  two  keepers,  whose  sole  duty 
is  to  attend  to  them,  are  a  pair  of  18-pounder  guns,  placed 
in  a  masonry  building  and  fired  through  embrasures,  in 
thick  and  foggy  weather,  at  intervals  of  fifteen  minutes, 
the  charges  being  three  pounds  of  powder. 

As  most  of  the  steamships  and  other  trade  to  Liverpool 
pass  quite  near  this  point,  and  fogs  are  common,  this  is  a 

steam -whistle  most  important  signal;  but  I  am  convinced  that  the  long 
guuf?inbu1eto  tlie  intervals  between  the  discharges  make  it  less  valuable  than 
a  powerful  steam-signal,  either  a  whistle,  siren,  or  Daboll 
trumpet,  would  be. 

It  is  to  be  remembered  that  an  increase  in  the  number  of 
discharges  would  materially  add  to  the  already  heavy  ex- 
pense. 

wind-guard  I  observed  on  the  dwelling  of  the  keeper  a  wind- guard, 
which  Mr.  Douglass  stated  was  designed  by  Faraday,  and  is 
in  common  use  in  the  light-house  service  as  well  as  through- 
out the  country.  In  the  most  trying  positions,  such  as 
North  Stack,  which  is  under  high  land  rising  immediately 
in  the  rear,  it  effectually  prevents  the  annoyance,  so  frequent 
in  such  localities,  of  the  smoke  being  driven  down  the  chim- 
ney during  high  winds.  A  sketch  of  this  chimney-top  is 
shown  in  Fig.  18. 

SOUTH  STACK. 

This  light-house,  at  the  extreme  westerly  point  of  Holy- 
head,  the  extremity  of  the  Island  of  Anglesea,  is  about  five 
miles  south  of  the  harbor,  in  a  remarkably  picturesque  lo- 
cality. 

From  the  elevated  laud  in  the  rear,  one  descends  by  a  flight 
of  450  steps  to  a  handsome  suspension-bridge  thrown  over 
the  chasm  separating  the  South  Stack  from  the  Island  of 
Anglesea. 

characteristics  This  light  is  catoptric,  revolving,  and  of  the  first  order, 
having  eleven  reflectors  on  each  face. 

rog-beii.  At  this  station  the  fog-bell,  weighing  two  and  one-half 

tons,  is  placed  with  its  mouth  uppermost.  A  counterpoise- 
weight  is  hung  underneath  the  axle,  which  is  turned  by 

Manner  o f  machinery  placed  under  cover.    The  hammer  is  within  the 
sounding  the  fog-  belL    Tne  axle  of  the  cog.wheel  w^ich  moves  the  bell  and 

its  counterpoise,  passes  through  a  slot  in  the  side  of  the 
machine-house,  and  has  a  slight  vertical  motion.  Great 
power  is  not  required  for  ringing  this  bell,  which  has  been 
in  use  for  many  years,  giving  entire  satisfaction  to  mariners. 


Plate  XXIII. 


FOG,     OR     OCCASIONAL    LIGHT     AT    SOUTH     STACK 
ST.    GEORGE'S     CHANNEL. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  157 

The  only  fog  or  "  occasional  "  light  for  use  at  light-stations    Fog  or  "  occa- 
in  thick  weather  of  which  I  have  any  knowledge,  is  at  South  81( 
Stack. 

It  is  well  known  that  while  lights  in  high  towers  and  on    High  lights  ob- 
considerable  elevations  of  land,  can  be  discerned  in  clear  8C 
weather  at  the  maximum  distance,  (in  our  service,  as  in 
others,  about  twenty  miles,)  an  object  of  the  first  importance, 
great  elevation  of  site  is  a  disadvantage  in  foggy  weather, 
since  the  fog-clouds  frequently  maintain  themselves  at  a  con- 
siderable height  above  the  sea,  and  envelope  the  light  when 
it  is  clear  below. 

At  many  points  in  our  Pacific  States,  the  coast  rises  so  Io£a8£ghtswhare 
abruptly  from  the  sea  that  no  sites  can  be  found  at  a  suffi-  eein  foggy 
ciently  low  elevation  to  avoid  this  difficulty,  even  when  low 
towers  are  erected,  and  the  arrangement  I  saw  at  South 
Stack  provides  a  remedy  for  the  obscuration  of  light  during 
foggy  weather. 

An  inclined  plane  has  been  excavated  in  the  rock,  and  a 
tramway  laid  thereon.  The  fog-light  is  contained  in  a  car- 
riage,  which  in  clear  weather  is  kept  at  the  summit  of  this 
plane  near  the  main  light-house,  but  during  a  fog  is  lowered 
by  means  of  a  windlass  to  a  position  where,  safe  from  the 
waves,  it  is  still  as  near  the  sea  as  possible.  The  forward 
part  of  this  movable  light-house  is  glazed,  and  contains  a 
catoptric  apparatus  of  three  reflectors  in  the  same  plane,  on  a 
revolving  frame  which  has  a  reciprocal  motion  through  the 
exact  arc  to  be  illuminated,  thus  giving  the  characteristics 
of  the  main  light. 

A  weight  for  driving  the  machinery  in  this  case  being,  as  du^naDSth°ef 
is  evident,  out  of  question,  the  motion  is  produced  by  means   °I1 
of  a  powerful  spring. 

This  ingenious  light  has  been  in  operation  for  many  years, 
(I  believe  since  1832,)  and  has  proved  to  be  of  great  advan- 
tage. Captain  Moodie,  of  the  Cunard  line,  with  whom.  I  re- 
turned to  America,  told  me  that  frequent  occasions  had  been 
afforded  him  for  testing  its  value,  the  light  at  Holyhead 
being  of  the  first  importance  to  the  immense  traffic  through 
Saint  George-'s  Channel,  where,  at  some  seasons  of  the  year, 
habitual  fogs  prevail.  Plate  XXIII  will  give  an  idea  of  this 
construction. 

Before  closing  my  notes  in  regard  to  the  English  light- 


i  •          -r    j    i  i  •  it*  ment   of     atten- 

house  service,  I  take  pleasure  in  recording  my  obligations  tions     received 
to  Sir  Frederick  Arrow,  the  Deputy  Master,  to  the  Elder  £S?     ** 
Brethren,  and  to  Mr.  Douglass,  the  engineer  of  the  Trinity  Hou8e< 
House,  for  the  attentions  and  kindnesses  of  which  I  was 
constantly  the  recipient,  from  the  time  I  arrived  in  England 


158  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

till  my  departure  for  America.  There  was  no  facility  for 
acquiring  information  in  regard  to  the  object  of  my  journey, 
no  act  of  hospitality  which  could  suggest  itself,  which  was 
not  proffered  with  that  hearty  generosity  for  which  their 
countrymen  are  distinguished. 

Drawings,  de-     While  in  London  I  was  furnished  with  drawings,  descrip- 
SveT'ffom  tions,  &c.,  of  many  of  their  light-houses  and  accessories,  and 
Trinity  House.    sjnce  my  retum  I  have  received  others  which  have  been  of 
much  assistance  to  me  in  the  preparation  of  this  report,  and 
I  am  happy  to  believe  that  such  relations  are  now  estab- 
lished as  will  lead  in  the  future  to  that  interchange  of  infor- 
mation which  is  desirable  in  this  most  interesting  and  im- 
portant service. 

Although  I  should  have  been  glad  to  avail  myself  of  the 
kind  invitation  of  Admiral  Schomberg,  Harbor-Master  at 
Holyhead,  to  whom  I  am  indebted  for  polite  attentions,  to 
remain  to  witness  the  demonstration  which  was  to  celebrate 
the  completion  of  the  great  breakwater,  the  limited  time  at 
my  disposal  would  not  permit,  and  on  my  return  from  South 
Stack,  the  last  English  light-station  that  I  visited,  I  em- 
barked in  the  Irish  mail-steamer  for  Dublin. 

IRISH  LIGHTS. 

Letter     from     Soon  after  my  arrival  in  England  I  received  the  follow- 
iSTigh?f rsof  ing  letter  from  the  Commissioners  of  Irish  lights : 

"  IRISH  LIGHTS  OFFICE, 
"  Westmoreland  Street,  Dublin,  May  24,  1873. 
tl  SIR  :  The  Commissioners  of  Irish  lights  having  been  in- 
formed by  the  inspector  of  lights  to  this  department  that 
you  propose  visiting  Ireland  shortly,  and  that  you  were  de- 
sirous of  availing  yourself  of  such  opportunity  to  inspect 
one  or  more  of  the  gas  light-house  establishments  under  the 
management  of  this  Board,  I  have  the  pleasure  to  acquaint 
you  that  the  Commissioners  will  be  most  happy  to  afford  you 
every  facility  to  carry  out  your  wishes. 

"  Will  you  be  so  kind  as  to  let  me  know  a  day  or  two  pre- 
viously, as  to  the  probable  period  of  your  arrival  in  Ireland  ? 
"  I  have  the  honor  to  be,  sir,  your  obedient  servant, 

"W.  LEES, 

"  Secretary." 
"  Major  GEORGE  H.  ELLIOT, 

"  Corps  of  Engineers,  United  States  Army." 

I  reached  Dublin  on  the  16th  of  August,  and  on  my  ar- 
rival proceeded  to  the  office  of  the  Commissioners,  where  I 
was  politely  received  by  Mr.  Lees,  who  seated  that  the  Com- 


ISITY 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  159 

missioners  were  at  that  moment,  according  to  previous  ar- 
rangement, embarking  for  Holyhead  to  take  part  in  the 
celebration  at  that  place,  and  wished  him  to  convey  to  me 
their  regrets  that  they  were  unable  to  meet  me,  and  to  in-  T  inspection  <>i 

J  Irish    gas-lights, 

form  me  that  Captain  Hawes,  the  inspector  of  Irish  lights,  with  Captain 
(whom  I  had  the  pleasure  of  meeting  at  South  Foreland  on  Wigiuw*. 
the  Straits  of  Dover  at  the  commencement  of  the  fog-signal 
experiments  of  which  I  have  given  an  account,)  and  Mr. 
Wigham,  .  the    inventor  of  the  Irish   gas-light  for  light- 
houses, would  take  me  to  such  of  their  establishments  as  I 
should  desire  to  visit. 

We  soon  set  out  by  rail  for  Howth  Baily,  the  northern 
head  of  Dublin  Bay,  where  is  a  first-order  fixed  gas-light  ; 
after  describing  this  station  and  that  at  Wicklow  Head, 
where  is  a  first-order  intermittent  gas-light,  I  shall  give  a 
general  description  of  the  Irish  gas-lights  for  light-houses, 
derived  from  information  received  from  Captain  Hawes  and 
Mr.  Wigham  as  well  as  from,  observations  made  on  my 
visits  to  the  above-named  stations,  and  to  the  English  gas- 
light at  Haisborough. 

HOWTH  BAILY. 

This  station,  (see  Plate  XXIV,)  on  a  bold  promontory  at    First  light 

J  where  Wigham's 

the  outer  northern  limit  of  Dublin  Bay,  is  of  interest  as  g^-  light     was 
being  the  first  station  at  which  the  Irish  gas-light  patented 
by  Mr.  Wigham  was  established  ;  this  was  in  1865. 
An  inspection  of  Plate  XXY  will  show  the  compactness    Little  space 

_    .  ,  ...  _,       required  for  gas- 

of  the  gas-works,  comprising  retort-house,  gas-holder,  &c.  works. 
Few  light-house  sites  are  too  limited  to  contain  buildings 
necessary  for  the  apparatus.     The  gas  holder  at  this  station 
contains  800  cubic  feet,  but  is  considered  too  small,  a  disad- 
vantage not  found  in  later  establishments  of  this  kind. 

Uniformity  of  pressure  of  gas  at  the  burners  is  obtained    uegubtor    to 
by  means  of  a  regulator,  also  of  Mr.  Wigham's  design;  and  Ft^of  p6re°sni-e™t 
I  will  here  mention  that  this  burner  is  but  one  of  many  ga 
curious  and  ingenious  inventions  led  to  by,  and  necessary 
for,  the  proper  development  of  the  system. 

As  at  Haisborough,  I  saw  here  from  actual  trial  that  the    Substitution  of 

r.  -,  •   -i     .  °*1   f°r  gas-light 

ordinary  first-order  oil-lamp,  which  is  always  ready,  can  be  when  necessary. 
substituted  for  the  gas  in  less  than  two  minutes,  and  the 

7  Changeof 


Irish  regulations  require  the  keepers,  for  the  purpose  of  jWs    required 
keeping  in  practice,  to  change  the  gas  for  the  oil  light  once 
a  month. 
The  changes  of  the  burners  and  the  mica  oxydizers  to    Manner  o* 


meet  the  varying  -atmospheric  conditions,  require  but 
instant,  the  change  of  the   burners   being   accomplished 


160  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

simply  by  setting  into,  or  lifting  out  of,  the  mercury-cups, 
the  short  pieces  of  supply-pipe  to  which  are  attached  the 
semi-cylindrical  rings  of  jets,  and  by  opening  or  changing 
the  cocks. 
bura^lS  Powf     The  largest  burner,  having  a  diameter  of  10J  inches,  con- 

r  of  flame.  tains  108  jets,  and  the  immense  body  of  flame  carried  to  the 
mouth  of  the  mica  oxydizer  (see  frontispiece)  is  most  daz- 
zling. 

Heat.  The  heat,  as  may  be  conceived,  was  very  great,  but  the 

keeper  said  it  gave  him  no  inconvenience,  nor  did  it  injure 
the  lenticular  apparatus,  thus  corroborating  the  information 
given  me  at  Haisborough.  The  lens  is  in  no  respect  dif- 
ferent from  the  ordinary  fixed  lens  of  the  first  order. 

Keepers.  Employed  at  this  station  are  two  keepers,  one  apprentice 

under  instruction,  and  a  gas-maker,  the  latter  receiving 
2s.  Qd.  (62J  cents)  a  day.  Captain  Hawes  considered  the 
employment  of  the  gas-maker  quite  unnecessary,  the  labor 
at  any  gas  light-house  being  easily  performed  by  two 
keepers. 

Eog-beii.  There  is  at  Howth  Baily  a  fog-bell,  operated  at  present 

by  an  Ericsson  engine,  but  for  some  years  a  gas-engine  was 
used,  which  was,  I  believe,  discontinued  in  consequence  of 
the  insufficient  size  of  the  gas-holder. 

Superiority  of     Mr.  Wigham,  who  constructed  the  works  at  both  Howth 

light  at    Howth 

Baily  and  Haisborough,  stated  that  at  the  former  place  the 
light  was  much  the  purer  and  whiter,  owing  to  the  burner 
being  supplied  under  much  greater  pressure.  Captain 
Hawes  is  of  the  opinion  that  28  jets  are  here  quite  enough 
in  clear  weather,  while  48  are  habitually  used  at  Hais- 
borough. 

WICKLOW  HEAD. 

This  station,  on  the  western  side  of  Saint  George's  Chan- 
nel, south  of  Dublin,  we  reached  partly  by  rail  and  partly  by 
"jaunting-car,"  a  two-wheeled  vehicle,  which  is  the  common 
conveyance  of  the  country. 
osn a        ^ne  gas-house,  containing  the  furnaces  and  retorts,  the 

works.  gas-holder,  and  other  buildings,  are  ingeniously  disposed  on 

the  face  of  a  high  cliff,  and  occupy  but  little  space,  as 
shown  by  Plate  XXVI. 
characteristics     This  is  a  first-order  intermittent  light,  the  lens-apparatus 

maniierlgof '  pro-  being  that  of  an  ordinary  fixed  light.  The  gas  is  let  on  and 
shut  off  by  an  automatic  arrangement  which  allows  ten 
seconds  of  light  and  three  seconds  of  darkness.  This 
arrangement  does  not  cut  the  gas  entirely  off,  and  each  jet 
during  the  three  seconds'  eclipse  shows  a  tiny  blue  flame, 
which,  while  it  produces  no  illumination  of  the  lenticular 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  161 

apparatus  and  can  scarcely  be  detected  in  the  daylight, 
is  still  sufficient  to  light  the  main  body  of  gas  when  the 
supply  is  turned  on. 

To  guard  against  all  danger  of  total  extinguishment  of    "By-pass,"  to 
the  light  by  gusts  of  wind  through  the  ventilators  or  door  jSg'ui 
of  the  lantern,  each  jet  is  surrounded  by  a  small  pipe  called  1J 
the  "  by-pass,"  the  top  of  which,  being  at  a  level  with  the 
tip  of  the  jet,  is  pierced  by  several  minute  holes  through 
which  gas  is  supplied  from  a  pipe  quite  independent  of  the 
automatic  cut-off;  thus  protected,  these  little  jets  of  flame 
burn  from  the  moment  of   lighting  at  sunset  to  that  of 
extinguishing  at  sunrise,  and  it  is  impossible  even  if  the 
"  cut-off"  or  a  gust  of  air  should  completely  extinguish  the 
main  flame  that  the  burner  should  not  be  lighted  at  regular 
intervals  of  thirteen  seconds. 

The  two  keepers  at  Wicklow  Head  agreed  with  those  at  ^ 
Howth  Baily  in  saying  that  the  gas  gives  very  much  less  us^t. 
trouble  than  the  oil  light. 

DESCEIPTION  OF  WIGHAM'S  GAS-APPAEATUS 
FOE  LIGHT-HOUSES. 

FIXED   GAS-LIGHTS. 

The  light  is  produced  by  a  burner  shown  in  the  Plates 
XXVII  and  XXVIII.    It  is  capable  of  producing  five  differ- 
ent  degrees  of  power  according  to  the  state  of  the  atmos- 5^. powers   of 
phere,  the  first  power  being  produced  from  28  jets  of  gas.    Fir8t  P°wer; 
Each  jet  consists  of  a  hollow  tube  with  an  ordinary  fish-tail 
burner  of  lava  at  the  top.    At  the  bottom  of  each  tube  is 
placed  a  small  lava  cone  bored  with  fine  holes,  (one  on  each    Regulator, 
side.)  the  effect  of  which  is  to  act  as  a  regulator  and  to  allow 
tbe  gas  to  enter  the  air  at  such  a  rate  of  speed  as  is  found 
most  conducive  to  its  combustion  in  connection  with  the 
overhanging  oxydator,  which  is  formed  of  talc,  and  which  is 
fitted  with  terminal  pieces  to  suit  the  respective  sizes  or  the 
various  powers  of  the  burner.    The  second  power  is  pro-    Second  power. 
duced  from  48  jets  as  above,  except  that  some  of  the  orifices 
in  the  lower  cones  are  slightly  larger  than  in  the  smaller 
burner.    The  third  power  is  from  68  jets,  with  slight  altera-    Third  power, 
tions  in  the  orifices  of  the  lower  cones  and  also  of  the  upper 
jets.    The  fourth  is  from  88  jets,  and  the  fifth  is  from  108    Fourth  and 
jets  as  above.    The  flame  of  the  latter  is  shown  in  the  frontis- fi 
piece. 

Tbe  rings  which  contain  the  jets  for  the  several  powers, 
except  the  first,  are  removable  and  replaceable  at  pleasure. 
Mercurial  cups,  each  fitted  witii  a  ground-in  valve,  are  the 
S.  Ex.  54 11 


162  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

means  employed  to  facilitate  this  application.     The  whole 
of  the  gas  supplied  to  the  burner  passes  through  a  chamber 
of  cast  brass,  at  the  bottomof  which  there  is  fixed  a  mer- 
curial lute  which   enables    the   whole    gas-burner  to  be 
removed  in  a  moment,  and  the  ordinary  oil-lamp  used  in 
and^substitution  dioptric  apparatus  to  be  substituted  for  it.    The  talc  chim- 
of  oii-iamp.        neys  are  also  removable,  and  arrangements  are  made  by 
which  the  ordinary  oil-lamp  condenser  can  be  fixed  for 
the  use  of  the  oil-lamp.     This  arrangement  for  rapidly 
substituting  the  oil-lamp  in  place  of  the>  gas-burner  was 
instituted  when  gas  was  first  lighted  at  Howth  Baily  light- 
house, in  the  year  1865,  as  a  precaution  against  any  acci- 
dent occurring  to  the  gas-light,  but  during  the  time  that  has 
since  elapsed  (about  eight  and  a  half  years)  no  occasion  has 
ever  arisen  for  putting  this  precautionary  plan  into  operation. 
Lenses  used.       By  the  use  of  gas  in  a  fixed-light  apparatus  of  any  size 
there  is  no  occasion  to  alter  the  existing  lenses,  but  in  some 
lanterns  it  may  be  necessary  to  provide  for  additional  ven- 
tilation.   It  will  be  seen  by  the  table  to  be  found  further  on 
that  the  photometric  values  of  the  flames  of  the  respective 
powers  of  the  gas-light  are  largely  superior  to  any  photo- 
metric results  obtained  from  the  oil-lamp,  either  for  paraf- 
Cost  of    gas- nne  or  colza  oil.    The  cost  of  gas-light  in  Great  Britain  is 
Ught<  said  to  be  less  than  that  of  oil,  comparing  only  the  ordinary 

power  of  the  gas-light.  Of  course,  when  the  fog-powers  of 
the  gas-light  are  turned  on,  the  cost  per  hour  is  greater,  but 
taking  the  average  of  a  year's  consumption  (including  con- 
sumption for  fogs)  at  several  light -houses  in  Ireland  which 
are  lighted  by  gas,  it  appears  from  a  return  made  by  the  en- 
gineer and  accountant  of  the  Board  of  Irish  Lights  that  there 
is  a  saving  of  about  £65  ($325)  per  annum  at  each  light- 
house by  the  use  of  gas  instead  of  oil. 

INTERMITTENT   GAS-LIGHT. 

Burner.  The  burner  used  in  this  case  is  precisely  the  same  as  that 

Flashes.  in  the  fixed  lights.  The  intermission  in  the  light  is  caused 
by  the  opening  and  shutting  of  a  gas-valve,  which  cuts  off 
the  supply  of  gas  to  the  burner  for  any  required  period, 
and  the  re-exhibition  of  the  light  takes  place  as  soon  as  the 
valve  is  opened,  a  small  by-pass  being  provided  for  keep- 
ing a  supply  of  gas  in  the  burner,  so  small  as  to  render  its 
flame  invisible,  but  sufficient  for  the  re-exhibition  of  the 
light  immediately  on  the  opening  of  the  valve.  The  open- 
ing and  shutting  of  this  valve  is  accomplished  by  means  of 
a  small  piece  of  clock-work  fixed  in  the  room  under  the 
lantern,  and  which  requires  to  be  wound  up  every  four,  six, 
or  eight  hours,  according  to  the  height  of  the  tower. 


Plate  XXVI. 


OAS     LIGHT-HOUSE     AT    WICKLOW     HEAD.    IRELAND. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  163 

Professor  Tyndall  very  clearly  illustrates  the  application  ^statemeut^  of 
of  the  intermittent  light  to  revolving  lenses  in  a  report  to  dafi.68 
the  Board  of  Trade  dated  the  7th  of  February,  1871. 

After  stating  that  a  gas-burner  of  28  jets  is  almost  iden- 
tical in  size  and  sensibly  equal  in  illuminating  power  to  the 
Trinity  four-wick  burner,  that  it  is  quite  as  applicable  as 
the  latter  to  a  revolving  light,  and  that  a  saving  can  be  se- 
cured by  a  periodic  extinction  of  the  gas-flame,  he  says : 

"The  central  octagon  figure  (see  Fig.  19)  from  which  the 
rays  issue  is  intended  to  represent  the  eight-paneled  re- 
volving apparatus.  The  points  of  the  stars  are  to  be  re- 
garded as  the  centers  of  the  beams  issuing  from  the  respect- 
ive panels.  The  blackness  of  the  disk  underneath  the  star 
is  intended  to  denote  the  darkness  of  night,  while  the  circle 
round  the  disk  represents  the  horizon. 

Fig.  19. 
K 


O 

Diagram  illustrating  revolving  intermittent  gas-light. 

"Every  part  of  the  horizon  receives  a  flash  every  second 
minute,  the  gas  being  lighted  one  minute,  during  which  the 
lens  is  moved  one  eighth  round,  and  each  part  receives  a 
flash,  then  the  gas  is  extinguished  one  minute,  and  so  on  in 
succession.  Thus  half  of  the  consumption  of  gas  is  saved. 

"  Let  the  star  be  turned  so  that  the  beam  A  shall  point  to  ^Description  of 
and  illuminate  the  station  K  on  the  horizon.    The  ray  B 
would  at  the  same  moment  illuminate  L ;  O  would  illumi- 
nate M ;  D,  N  $  E,  O  5  F,  P  ;  G,  Q ;  while  the  ray  H  from  the 
eighth  panel  would  illuminate  E,  the  eighth  station. 

"  Let  the  star  be  turned,  or  in  other  words  let  the  appa- 
ratus be  supposed  to  revolve,  until  A  reaches  L.  During 
this  time  B  travels  from  L  to  M  ;  C  from  M  to  N  ;  D  from 
N  to  O  5  E  from  O  to  P  ;  F  from  P  to  Q  ;  G  from  Q  to  E  ; 
and  H  from  E  to  K.  Thus,  through  the  passage  of  A  from 
K  to  L,  in  other  words  during  the  rotation  of  the  apparatus 
through  one-eighth  of  a  revolution,  every  point  on  the  horizon 
is  once  illuminated. 


164  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

"If  the  flame  continue  burning,  the  same  effect  is  pro- 
duced during  every  succeeding  eighth  of  a  revolution. 
Every  point  of  the  horizon  is  once  illuminated.  At  Eocka- 
bill  the  time  of  a  complete  revolution  is  ninety-six  seconds ; 
hence,  the  number  of  panels  being  eight,  as  in  the  model, 
each  point  of  the  horizon  receives  flashes  which  succeed 
each  other  in  intervals  of  twelve  seconds. 

u  But  suppose  at  the  moment  the  beam  A  points  toward 
L  the  supply  of  gas  to  be  cut  off,  and  the  apparatus  per- 
mitted to  revolve  in  darkness  until  A  reaches  M.  During 
this  eighth  of  a  revolution  no  gas  is  consumed,  and  no  flash 
is  received  by  any  point  on  the  horizon. 

"  When  A  reaches  M  let  the  gas  be  relighted.  During 
the  succeeding  eighth  of  a  revolution  every  point  of  the 
horizon  would  be  once  illuminated  as  before.  It  is  quite 
manifest  that  this  process  may  be  continued  indefinitely ; 
the  gas  being  lighted  and  every  point  of  the  horizon  once 
illuminated  during  every  alternate  eighth  of  a  revolution. 

"  It  is  also  plain  that  the  intervals  of  darkness  between 
the  flashes  instead  of  being,  as  they  now  are,  twelve  seconds, 
would  be  twenty-four  seconds.  This  reasoning,  which  as 
far  as  it  goes  is  of  the  character  of  a  mathematical  demon- 
stration, has,  as  stated  in  my  report  of  the  8th  of  October, 
been  verified  by  actual  observations  on  the  Eockabill  light. 

"  There  is,  as  far  as  I  can  see,  but  one  drawback  to  the 
perfection  of  this  scheme ;  and  this  I  will  now  try  to  point 
out  with  distinctness.  Let  the  beam  A  point,  as  at  the 
outset,  toward  K ;  at  a  certain  moment  we  start  from  K 
toward  L  with  the  gas  lighted.  According  to  the  new  scheme 
K  ought  to  be  in  absolute  darkness  for  twenty-four  seconds. 
But  just  as  A  reaches  L,  and  before  the  gas  is  cut  off,  a 
glimmer  is  seen  at  K,  this  glimmer  being  only  twelve  sec- 
onds distant  from  the  preceding  flash.  The  same  is  true  of 
the  other  seven  points  of  the  horizon  faced  by  the  panels  the 
moment  before  the  flame  is  extinguished.  In  all  the  remain- 
ing sweep  of  the  horizon  this  secondary  glimmer  is  absent." 

Professor  Tyndall  further  says  in  regard  to  this  glimmer 
that  he  noticed  it  in  his  experiments  at  Eockabill  light- 
house, but  attached  no  practical  importance  to  it;  and  that 
on  the  isolated  points  where  it  is  seen  it  is  so  masked  by  the 
superior  brilliancy  of  the  true  flash  that  no  mariner  could 
be  deceived  by  it. 

substitution  of     The  same  method  of  substituting  an  oil-lamp  for  the  gas- 
burner?         's  burner  is  arranged  for  intermittent  as  for  fixed  lights,  the 
only  difference  being  that  if  the  oil-lamp  were  used  the 
machine  which  actuates  the  cutting  off  of  the  gas  is  made 


o    il 


THE   IRISH   GAS   LIGHT. 

108  JET  BURNER. 

SECTION. 


PLATE  XX VII.   - 


o.  o.  1O8 


Tubes. 


4  Inches  to  1  Poot. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  165 

to  open  and  shut  semi-cylindrical  shades  for  eclipsing  the 
oil-lamp  for  the  required  period  of  darkness.  As  in  the 
case  of  Howth  Baily,  no  occasion  has  ever  arisen  at  Wick- 
low  for  falling  back  upon  the  oil-lamp  since  gas  was  lighted 
at  that  station,  about  seven  years  ago.  The  advantage  of  U8td0Vfa^ntfrnn°tf 
the  use  of  intermittent  lights  as  applied  to  gas  light-houses tent  nght- 
is  obvious,  for  during  the  period  of  darkness  the  consump- 
tion of  gas  is  saved,  whereas  in  the  case  of  oil-lights,  the 
flames  of  which  are  merely  eclipsed  by  shade,  the  consump- 
tion of  oil  continues  during  the  intervals  of  darkness  as 
well  as  during  the  intervals  of  light.  This  peculiarity  of 
gas  renders  its  use  for  intermittent  light  still  more  economi- 
cal than  for  fixed  lights.  All  the  four/o#-powers  of  the  gas- 
burner  may  be  intermitted  precisely  as  is  the  case  with  the 
first  or  ordinary  power. 

By  the  use  of  gas  in  an  intermittent-light  apparatus  there 
is  no  occasion  to  alter  the  existing  lenses. 

REVOLVING  GAS-LIGHTS. 

The  burner  used  in  this  case  is  precisely  the  same  as  that    Burners. 
in  the  fixed  and  intermittent  lights.    The  lenses  by  which    Revolution  of 
the  flashes  are  directed  to  the  observer  revolve  around  the lei 
gas-light  just  as  they  revolve  around  the  oil-light.     An 
arrangement  similar  to  that  in  fixed  lights  for  substituting 
the  oil-lamps  for  the  gas-burner  is  also  established.    The 
remarks  as  to  the  superiority  of  gas  over  oil  in  fixed  lights 
apply  equally  to  revolving  lights,  with  this  additional  advan- 
tage, that  by  the  use  of  gas-burners  whioh  have  large  diame- 
ters each  flash  is  of  longer  duration  than  in  the  case  of  the 
oil-lamp,  and  this  is  stated  to  have  been  highly  appreciated 
by  mariners. 

GROUP-FLASHING    GAS-LIGHTS. 

The  burner  used  in  this  cassis  precisely  the  same  as  that  Burner, 
in  fixed  lights.  The  groups  of  flashes  are  caused  by  the  con-  Flashes. 
tinual  extinction  and  re-ignition  of  the  gas-flame.  This  is 
accomplished  by  similar  means  to  that  which  causes  the  in- 
termission of  a  fixed  light,  except  that  the  machinery  which 
causes  the  lenses  to  revolve  is  availed  of  for  actuating  the 
cutting-off  gas- valves  instead  of  a  special  machine  being 
provided  for  that  purpose.  By  means  of  this  system  of 
group-flashing  the  same  economy  may  be  attained  which 
the  use  of  gas  presents  in  the  case  of  intermittent  lights,  with 
this  difference,  that  the  economy  is  always  at  a  fixed  ratio, 
viz,  about  one-half  the  consumption  of  the  gas.  The  lenses 
are  continually  revolving  and  the  gas-light  is  continually  in- 
termitting. By  reducing  the  speed  of  the  revolutions  of  the 


16G  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

lenses  (which  themselves  require  no  alteration  for  this  sys- 
tem) a  group  of  seven  or  eight  distinct  and  powerful  flashes 
recurring  at  regular  intervals  may  be  obtained,  and  the  effect 
of  this  kind  of  light  is  said  to  be  exceedingly  arresting  to 
the  eye  of  the  mariner. 

TRIFORM  FIXED    GAS-LIGHT. 

Three  burners  This  light  is  produced  by  three  burners  similar  to  that 
above  described,  placed  vertically  over  each  other  as  shown 

Air-chambers  in  Plate  XXIX,  but  the  two  upper  burners  are  surrounded  by 
ers.  "r  n  two  air-chambers  for  the  supply  of  pure  air  to  the  flame  and 

the  carrying  off  of  the  foul  air  from  the  flame  of  the  burner 
below.  Tubes  for  the  introduction  of  pure  air  are  placed 
obliquely  in  these  chambers,  and  the  effect  of  the  arrange- 
ment is  that  not  only  are  these  three  burners  of  equal  power 
when  in  a  light-house  lantern  in  place  of  one  as  in  an  ordi- 
nary case,  but  the  light  is  much  intensified  by  the  manner 
in  which  the  burners  are  supplied  with  heated  air. 

Description  of  In  the  plate,  a  is  the  main  supply-pipe,  &,  &',  ~b"  are  the  gas- 
burners,  c,  c'  are  the  distributing-pipes,  d,  d',  d"  ;ire  the  mica 
chimneys,  e,  e',  e"  are  the  sheet-iron  chimneys,/,  /'  are  the 
outer  air-chambers,  ft,  li1  are  flues  leading  to  the  inner 
air-chambers  </,  g',  which  at  their  lower  ends  have  the  form 
of  inverted  cones ;  *  is  the  main  escape  pipe,  and  fc,  ft,  ft  are 
the  refracting  belts. 

Removal  of  top     The  top  and  bottom  prisms  of  the  dioptric  apparatus  are 

and    bottom 

prisms.  removed,  and  instead  of  them  segments  of  refracting  belts 

are  placed  above  and  below  the  central  belt  of  the  dioptric 
apparatus.     (See  Fig.  1,  Plate  XXX.) 
Amount  of  gas     The  consumption  of  gas  in  this  form  of  apparatus  is  three 

consumed.  ^m^  that  of  the  single  lamp,  but  the  quantity  of  light  is 
more  than  three  times  as  great.  We  must,  however,  deduct 
the  light  which  would  be  transmitted  from  the  top  and  bot- 
tom prisms  of  the  single  lamp  apparatus,  which  is  valued  at 
about  one-third  of  the  whole  apparatus,  and  it  may  be  said 
that  the  light  of  a  light-house  illuminated  by  the  triform 
Ratio  of  iiiu-  apparatus  is  to  that  of  a  light-house  illuminated  by  a  single 

a^uced^trfform  lamp  and  an  ordinary  lenticular  apparatus  as  2  to  1.     It 

light  and  8inglewjllbeseen  by  the  tabie  of  photometric  values  that  the 
power  of  the  largest  size  of  the  gas-burner  is  stated  by  Mr. 
Wigham  to  be  equal  to  2,577  candles.  Assuming  this  to  be 
correct,  there  is  therefore  transmitted  by  means  of  triform 
apparatus  three  times  that  amount,  viz,  light  equal  to  7,731 
candles,  and  if  this  is  increased  more  than  eighteen  times 
by  the  agency  of  the  cyliudric  refractors,  as  is  the  case 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  167 

where  the  ordinary  oil-burner  is  used  in  a  first-order  fixed 
lens,  the  immense  power  of  more  than  139,158  candles  is 
transmitted  to  the  observer.  This  power,  great  as  it  is,  is 
of  course  exceeded  by  the  triform  light  in  revolving  ap- 
paratus. 

TRIFORM  INTERMITTENT   GAS-LIGHT. 

The  apparatus  in  this  case  is  precisely  similar  to  that 
described  for  intermittent  lights  with  one  lamp,  except  that 
refracting  belts  are  substituted  for  top  and  bottom  prisms 
as  described  in  the  case  of  the  triform  gas-apparatus  for 
fixed  lights. 

TRIFORM  REVOLVING  GAS-LIGHTS. 

The  arrangements  of  burners,  lenses,  &c.,  are  nearly  similar  of 
to  those  for  fixed  lights.  The  lenses  are  placed  vertically  es,  &c. 
(see  Fig.  2,  Plate  XXX)  in  order  to  give  the  most  power- 
ful beam  that  can  be  transmitted  to  the  horizon,  but  in  case 
it  were  desired  that  the  ordinary  flash  should  recur  more 
frequently  than  is  possible  with  an  apparatus  containing 
only  one  light,  the  lenses  may  be  placed  eccentrically,  as 
shown  in  Fig.  3,  Plate  XXX,  and  this  in  a  very  striking 
manner  attains  that  object. 

TRIFORM  GROUP-FLASHING  LIGHT. 

The  remarks  made  under  the  head  of  group-flashing  light 
for  a  single  lamp  apply  equally  in  this  case,  but  the  groups 
of  flashes  proceed  from  three  lenses  in  place  of  one,  and  are 
consequently  of  much  greater  power. 

EXPERIMENTS  WITH  THE  TRIFORM  LIGHT. 

On.  the  evening  of  our  return  from  Howth  Baily  to  Dub- 
lin we  proceeded  to  a  point  near  Kingstown,  on  the  south 
side  of  Dublin  Bay,  distant  six  miles  from  the  Howth  Baily 
fixed  gas-light,  to  observe  some  experiments  to  be  made    Experimental 
with  a  triform  light,  (previously  placed  temporarily,  for  pur-  tw™eif fixed  ami 
poses  of  experiments  made  under  direction  of  Professor ngii£s0rm  gai 
Tyndall,  in  a  small  cabin  near  Howth  Baily  light,)  arrange- 
ments for  which  had  been  made  by  Captain  Hawes  and  Mr. 
Wigham  while  we  were  at  that  station. 

The  three  Wigham  burners,  each  capable  of  burning  from  Arrangements 
28  to  108  jets,  were  placed  vertically  over  each  other  in  the 
foci  of  three  panels  of  the  refracting  belt  of  a  first-order  lens, 
as  already  described,  stop-cocks  being  provided,  so  that  any  Manner  of  in- 
of  the  rings  of  either  burner  could  be  lighted  or  extinguished  creasing  light!*6" 


168  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

at  pleasure.  The  principal  keeper  at  the  station  had  re- 
ceived instructions  to  cover  and  uncover  the  catadioptric 
prisms  of  the  first-order  lens  in  the  tower,  while  the  assist- 
ant was  to  vary  the  powers  of  the  triform  lights,  both  act- 
ing according  to  a  memorandum  given  to  each,  a  copy  of 
which  we  were  provided  with. 

Programme  of  experiments  with  a  triform  light  at  Howth  Bally,  Dublin 
Bay,  August  6,  1873. 


Tower  lights. 

Triform  lights. 

P.M. 

9.  30.  —  28  jets  ;  cover  the  catadioptric  prisms  .  .  . 
9.  35.—  28  jets  ;  uncover  catadioptric  prisms  
9.  40.  —  28  jets  ;  catadioptric  prisms  uncovered  .  . 
9.  45.  —  28  jets  ;  catadioptric  prisms  uncovered  .  . 
9.  50.—  28  jets  ;  catadioptric  prisms  uncovered  .  . 
9.  55.  —  108  jets  ;  catadioptric  prisms  uncovered  . 
10.  00.  —  28  jets  ;  catadioptric  prisms  uncovered  .  . 
10.  05.  —  End  of  experiments. 

P.M. 

9.  30.—  28  lets  ;  upper  belt  only. 
9.  35.—  28  jets  ;  the  three  belts. 
9.  40.—  48  jets  ;  the  three  belts. 
9.45.—  68  jets  ;  the  three  belts. 
9.  50.—  88  jets  ;  the  three  belts. 
9.  55.—  108  lets  :  the  three  belts. 
10.  00.—  108  jets  ;  the  three  belts. 

Appearance  of     From  our  point  of  observation  at  Kingstown  the  28-jet 
light,  shown  only  in  the  upper  belt  of  the  triform  arrange- 
ment, appeared  slightly  inferior  to  the  28-jet  light  in  the 
tower  when  the  catadioptric  prisms  were  covered.    They 
should  have  appeared  equal,  but  the  difference  is  accounted 
Reason  for  in- for  by  the  facts  that  the  ventilation  of  the  cabin  and  the 
ngh°triburninf  ^n  °^  refracting  belts  used  for  the  experiments  were  imperfect, 
the?rifoermbappa-an(i  neitoer  tne  latter  nor  the  glazing  of  the  window  were 
ratus.  so  ciear  as  jn  the  lantern  of  the  tower-light. 

When  the  catadioptric  prisms  of  the  tower-light  were 
uncovered  and  the  entire  beam  from  the  lens  thus  coming 
to  our  view  was  compared  with  the  triform  lights,  changed, 
Su  eriority  ofas  snown  *n  ^ne  table,  from  84  to  324  jets,  the  superiority 
the  triform-light,  of  the  latter  was  very  marked,  it  having  the  appearance  of 
a  great  globe  shining  with  a  pure  and  dazzling  white  light. 
The  effect  of  the  changes  in  the  triform  light  was  peculiar, 
and  one  could  hardly  believe  that  he  was  observing  two 
lights  equally  distant  from  him,  for,  as  the  power  of  this 
light  was  gradually  increased,  the  one  in  the  tower  appeared 
rapidly  to  recede  and  to  be  thrown  further  and  further 
to  the  rear,  so  that  when  108  jets  burned  simultaneously 
behind  each  of  the  refracting  belts,  the  tower-light,  burning 
28  jets  and  equal  in  power  to  an  ordinary  first-order  oil- 
light,  appeared  to  have  receded  many  miles,  and  to  have 
dwindled  until  it  presented  the  appearance  of  a  star. 

When  108  jets  were  burning  in  the  tower  the  comparison 
with  the  triform  light  of  324  jets  was  still  very  much  in 
favor  of  the  latter,  though  the  superiority  was  not  so 
marked. 


THE  IRISH  GAS-LIGHT. 


PLATE  XXVII I, 


28-JET   BURNER. 


EUROPEAN   LIGHT-HOUSE   SYSTEMS. 


169 


It  may  be  well  to  state  that  the  columnar  form  which  the    Form  of   the 

triform  light  like 

triform  light  might  be  supposed  to  assume  is  not  observ-  the  other  in  ap- 
able,  as  from  Kingstown  it  appeared  to  us  of  precisely  the  pe 
same  shape  as  the  single  light  in  the  tower. 

ILLUMINATING  POWERS  OF  GAS-LIGHTS. 

The  following  are  the  results  of  observations  recently 
made  with  a  photometer,  as  stated  to  me  by  Mr.  Wigham : 


Gas-burn- 

Consumption 

Illuminating  power, 
the  unit    being  a 

ers  —  No.  of 

in  cubic  feet 

sperm  candle,  con- 

jets. 

per  hour. 

suming  120  grains 

per  hour. 

28 

50 

330.  68 

48 

100 

668.28 

68 

150 

1,  002.  09 

88 

220 

1,  667.  49 

108 

290 

2,577.3 

Additional 


In  this  connection  it  should  be  observed  that  Trinity    illuminating 
House  four-  wick  oil-lamp,  as  improved  by  Mr.  Douglass, 
consuming  34.13  ounces  per  hour,  (160  ounces  to  the  impe- 
rial gallon,)  gives  an  illuminating  power  equal  to  328.18 
sperm-  candles. 

According  to  actual   experiments,  the  first-order  fixed 
dioptric  apparatus  transmits  to  the  mariner  27.39  times,  and 
the  first-order  revolving  apparatus  of  eight  panels  338.74  paBytU8revoMng 
times,  more  light  than  the  unassisted  first-order  oil-lamp.  appar 
These  ratios  would  give  for  single  lenses  illuminated  by  Wig- 
ham's  gas-burners  of  108  jets  powers,  equal  respectively  to 
70,592  and  to  873,034  candles.    It  is  stated  (see  M.  Reynaud's 
Memoire  sur  Vlficlairage  des  Cotes  de  France)  that  the  lumi- 
nous beams  from  the  refracting  belt  '  of  a  dioptric  appa-    Power 
ratus  for   a  fixed  light  of  the  first  order  is  .7   of   the  firTt-o?! 
beam  from  the  entire  lens,  and  that  the  beam  from  the 
refracting  portion  of  one  of  the  panels  of  a  revolving  octag- 
onal lens  of  the  first  order  is  .647  of  the  entire  beam  ;  also 
that  in  the  first  case  the  power  of  the  refracting  portion 
of  the  lens  is  19.13,  and  in  the  last  case  218.1  times  more 
powerful   than   the   unassisted  first-order   oil-lamp.     The 
same  ratios  for  triform  lights,  supposing  each  lamp  to  burn 
108  jets,  would  give  for  the  fixed  light  147,914  candles,  and 
for  the  revolving  light  1,686,228  candles  !    I  am  not  aware    The  above  re- 
that  any  experiments  have  been  made  of  the  actual  powers  inpracSce,owing 
of  lenses  illuminated  by  gas-lights,  but  as  a  considerable  % 


of 


fixed. 


Revolving. 


Ratios  applied 
to  triform  lights. 


170 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


portion  of  the  light  is  exfocal,  the  divergence  is  so  much 
increased  that  the  above  results  would  be  very  far  from 
holding  good  in  practice. 
Results  arrived     I  should  further  add  in  regard  to  photometric  experi- 

at  bv   Professor  ,  -IT  TUT-    i          •>  i 

Tyndaii  on  ex-  mental  comparison  between  oil  and  Wigham's  gas-burners 
for  light-houses  that  Professor  Tyndall  arrived  at  the  fol- 
lowing results : 

(The  four-wick  lamp  being  taken  as  the  unit,  the  illumi- 
nating power  of  the  gas-flame  is  expressed  in  terms  of  that 
unit. ) 


Four-wick 
lamp. 

Number  of 
jets. 

Gas-flame. 

28 

2* 

48 

41 

68 

6 

88 

9f 

108 

13 

That  is  to  say,  the  photometer  showed  the  28-jet  flame  to 
have  two  and  one-half  times,  the  48-jet  flame  four  and  one- 
half  times,  the  68-jet  flame  six  times,  the  88-jet  flame  nine 
and  three-fourths  times,  and  the  108-jet  flame  thirteen  times 
the  illuminating  power  of  a  four-wick  flame  of  a  first-order 
sea-coast  light-house  lamp. 

The  above  ex-     It  should  be  mentioned  in  this  connection  that  these  ex- 
periments   ante-  ,     ,  .  ,  .  .  , 

nor    to   recent  penments  were  probably  made  anterior  to  the  improvement 

iSpSmers!8  in  in  oil-lamps  made  by  Mr.  Douglass,  the  present  power  of 
his  four-wick  lamp  as  compared  with  the  lamp  formerly 
used  being  as  328  to  2G9. 

COST  OF  WIGHAM'S  GAS-LIGHT  APPARATUS  FOR  LIGHT- 

HOUSES. 

Costofappara-     Mr.  Wigham  informed  me  that  the  cost  of  gas-making 
shipmSJand  d°er  apparatus  of  a  size  similar  to  that  used  at  the  Irish  stations, 
Liver-  Eockabill>  Wicklow  Head?  Hook  i>Ower,   and  Mineheacl, 

packed  and  delivered  at  Liverpool  ready  for  shipment, 
would  be,  for  a  single  tower,  about  £1,000,  ($5,000,)  and  for 
Resulting  cost  a  station  with  two  towers,  like  that  at  Cape  Ann  or  High- 
ifgbKfclpe  lands  of   Navesink,   about  £1,600,  ($8,000.)     These  esti- 
Arm,   or  Nave-  mates  inciucie  furnaces,  retorts,  gas-holders,  and  tanks  for 
the  same,  together  with  the  burners  and  every  other  item 
of  expense  except  the  freight  from  Liverpool  to  America, 
the  cost  of  erection  at  the  site,  and  the  additional  buildings 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  171 

required.     The  expense  of  the  latter  item  is,  in  Ireland,    Expense  of 
about  £250,  ($1,250,)  and  in  the  United  States  would  bebu 
somewhat  larger  hi  consequence  of  the  higher  price  of  labor. 

Mr.  Wigham  further  stated  that  he  would  personally  in-  w£^di^n  *w?* 
spect   any   site  at   which  the  United  States  Government  ham  yould  con- 

J  sent   to   erect   a 

might  desire  to  use  his  apparatus,  and  give  the  Board  all  gas-light  appara- 

tus  in  the  United 

the  information  and  assistance  in  his  power,  on  condition  states. 
that  his  traveling  and  other  expenses  be  paid;  also  that  he 
would  bring  with  him  for  the  purpose  of  assisting  in  and 
superintending  the  erection  of  the  entire  work,  one  of  his 
most  competent  foremen,  the  charge  for  whose  time  would 
be  10s.  6d.  ($2.62)  per  day  in  addition  to  his  expenses  for 
board,  lodging,  and  traveling. 

In  regard  to  the  use  of  his  gas-light  in  the  United  States 
Mr.  Wigham  stated  that  although  his  patent  did  not  extend 
to  this  country  he  would  have  no  hesitation  in  building  a 
gas-light  for  our  use,  having  no  fear  but  that,  should  others 
be  required,  his  labors  for  the  improvement  of  light-house 
illumination  would  be  recognized  and  rewarded. 

COST   OF  THE    TRIFORM-LIGHT    APPARATUS. 

The  cost  of  this  gas-apparatus  is  greater  by  about  £250    Cost  of  triform 
($1,250)  than  for  the  ordinary  single-light  apparatus. 
The  expense  of  removing  the  upper  and  lower  catadiop-. 


tric  prisms  of  the  lens  and  substituting  for  them  two  refract-  paratnfo    the 
ing  belts  is  in  Ireland  not  great,  as  Chance,  Brothers  &  Co.,  r 
who  supply  most  of  the  lenticular  apparatus  for  the  British 
lights,  offer  to  take  the  prisms  of  the  first-order  lens  in  ex- 
change for  refractors  on  payment  of  a  difference  of  £150, 
($750,)  provided  the  prisms  are  of  their  own  manufacture. 
If  a  new  light-house  were  building,  or  if  a  new  dioptric 

Cost  of  placing 

apparatus  were  to  be  placed  in  an  existing  light-house,  it  triform   lens-ap- 

..  ,       parutus  less  than 

would  be  rather  less  expensive  to  have  it  arranged  on  the  that  of  the  or<u- 
triform  system  than  in  the  ordinary  way,  with  a  central  beltna 
and  upper  and  lower  catatlioptric  prisms. 

COST  OF  MAINTENANCE   OF  GAS-LIGHTS. 

The  use  of  tar  for  fuel  in  Great  Britain  within  the  last    Use  of  tar  for 
few  years  has  so  lessened  the  cost  of  production  of  gas  that 
it  may  be  calculated,  it  is  stated,  not  to  exceed,  even  at  out- 
lying stations,  10s.  ($2.50)  per  thousand  feet,  including  4  per 
cent,  interest  on  the  original  outlay  for  apparatus. 

If  gas  could  be  supplied  to  our  light-houses  at  this  rate     Approximate 

}  animal    cost     of 

the  cost  per  annum  to  a  first-order   seacoast-light,  burning  gas- 
habitually  28jets  during  the  average  period  of  illumination, 


172  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

(4,311  hours,)  would  be  $550  ;  adding  for  ail  extreme  case  (as 
West  Quoddy  Head  on  the  coast  of  Maine  for  example)  20 
per  cent,  for  additional  consumption  in  foggy  and  thick 
weather,  we  have  $660  as  the  approximate  annual  cost  of 
the  gas  for  such  light, 
cost  of  annual  The  annual  consumption  of  oil  in  our  light-houses  of  the 

consumption   Of  flrgt  Qrder  ig  &^Qut  7QQ  gSL\\oll^  amounting  at  the  last  aver- 
age contract-price  of  89  cents  per  gallon  to  $676.40. 
Less  cost  for     At  stations  with  two  towers  the  cost  per  thousand  feet  is 

§jetpat  tstSns  considerably  less  than  at  single  tower-stations,  since  the  cost 

SSuawhere^re^  the  labor  and  other  items  is  proportionately  less  the 

is  but  one.         greater  the  quantity  manufactured. 

ILLUMINATION  OF  BEACONS  BY  GAS. 

Beacons  on  out-     Mr.  Wighani  has  devised  an  arrangement  for  lighting  by 
lying  rocks.        g^  beacons  on  detached  rocks  which  are  inaccessible  dur- 
ing heavy  weather.     Gas  for  the  illumination  of  such  posi- 
tions cannot  ordinarily  be  carried  in  submarine  pipes,  on 
account  of  the  condensation  of  moisture  within  the  pipe, 
the  lowest  part  thus  becoming  filled  with  water  and  the 
flow  of  gas  being  consequently  obstructed, 
prying  gas     Mr.  WighanVs  plan  is  to  dry  the  gas  by  chloride  of  cal- 

with  chloride  of.  ,,  TIJ  T  J-TI  j.»          •   i 

calcium.  cium,  and  he  proposes  to  light  and  practically  extinguish 

the  beacon  by  means  of  variations  of  the  pressure  of  gas  in 
the  supply -pipe ;  that  is  to  say,  a  high  pressure  of  gas,  say 
of  six  inches  of  water,  closes  a  stop-cock  at  the  beacon  and 
keeps  it  closed  during  the  day;  at  the  time  of  lighting,  this 
pressure  is  decreased  to  the  ordinary  working-pressure  of, 
say,  three  inches  of  water,  and  the  cock  opens.  The  burner 
is  lighted  by  means  of  a  little  flame  supported  by  a  small 
"  by-pass,"  such  as  preserves  the  light  from  extinguishment 
during  eclipses  at  the  Wicklow  Head  intermittent  light 
heretofore  described.  The  full  power  of  the  light  can  be 
kept  up  till  sunrise,  when  the  increased  pressure  of  gas  closes 
the  cock  arid  extinguishes  the  beacon. 
The  invention  Experiments  sufficient  for  determining  the  utility  of  this 

not  yet  tuiiy  test- .nveil||OI1  nave  not  ye^  been  made  ;  but  it  seems  a  step  in 

the  right  direction,  and  affords  another  indication  of  the  in- 
genuity of  Mr.  Wighani. 

opinions  of  the     I11  concluding  my  remarks  on  the  subject  of  gas  as  an 
ot  ^^minant  for  light-houses,  I  will  only  say  that  the  Irish 
Board  and  its  officers  state  most  positively  that  the  actual 
use  of  gas  at  five  of  its  sea-coast  stations  proves  it  to  be 
Annual  saying  more  economical  than  oil,  and  specifically,  at  Howth  Baily 
atHowthBaiiy.  the  gaving  ja  £50  ($250)  annually,  taking  into  account  all 


THE  IRISH  GAS-LIGHT. 
TRIFORM  BURNERS. 


PLATEXXIX. 


_Znc/ieSi2      9       6       3      O 


SCALE . 


-  Feet. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  173 

expenses  of  making  gas  and  the  interest  on  the  first  cost  of 
apparatus. 
Professor  Tyndall  states  that  the  28-jet  burner,  the  lowest    Opinion  of  pro- 

7  .     _     .         .     fessor  Tyndall  as 

power  of  the  gas-lamp,  gives  a  light  in  no  degree  inferior  to  to  the  compara- 

the  first-order  four-wick  oil-lamp  used  in  light-houses.  and  wi7ights.gas 

The  oil-lamp  is  susceptible  of  few  variations  in  regard  to    variability  in 

regard  to  power 

power,  (our  lamps  have  none :  the  Douglass  six-wick  lamp  not  possessed  by 

*  oil-lamps,  except 

used  by  the  Trinity  House  has  three,  and  the  power  of  the  those  of  Mr. 
light  can  be  increased  from  324  to  722  caudles;)  while  the  patent!88 
gas-light  of  the  triform   system  can   be  carried  through 
many  more  gradations  reckoning  from  the  lowest,*  so  that 
a  skillful  keeper  can  suit  his  light  to  any  condition  of  the 
atmosphere. 

Assuming  the  facts  to  be  as  stated  by  Professor  Tyndall,    Either  the  four- 
either  the  four-wick  oil-lamp  or  theWigham  28-jet  gas-lamp  a&jet  a  sufficient 
are  sufficient  in  clear  weather  to  send  their  rays  from  the fairweather. 
lanterns  of  sea-coast  towers  to  the  sea-horizon  a  distance  of 
twenty  miles. 

As  has  been  stated  in  speaking  of  Haisborough,  no  light 
which  has  been  or  ever  can  be  invented  can  be  seen  through 
a  dense  fog,  which  obscures  even  the  sun  itself. 

It  will  be  seen,  therefore,  that  the  required  improveme 
in  sea-coast  lights  is  that  of  a  varying  capacity  of  power  po 
that  can  be  suited  to  all  stages  of  the  atmosphere,  and  the  weather. 
Irish  gas-light  certainly  appears  to  me  to  meet  this  require- 
ment more  fully  than  any  other  known,  with  this  additional    Additional  ad- 
advantage:  during  the  eclipses  of  revolving  and  intermit-  omyaine  flashing 
tent  lights  the  consumption  of  the  illuminant  may  be  en- ga 
tirely  suspended,  and  when,  as  is  often  the  case,  the  total 
amount  of  eclipses  is  six  hours  or  more  out  of  twelve,  the 
economy  is  evident, 

Professor  Tyndall,  in  one  of  his  reports  to  the  Board  of 
Trade,  thus  sums  up  his  conclusions : 

"  The  results  assure  me  that  with  gas  as  a  source  of  illumi-    Conclusion   of 

.    ,  ,  Professor      Tyn- 

nation  an  amount  of  variableness  and  consequent  distinct-  daii. 
iveness  is  attainable  which  is  not  attainable  with  any  kind 
of  oil.  It  would,  I  think,  be  easy  to  give  to  every  light- 
house supplied  with  gas  so  marked  a  character  that  a 
mariner  on  nearing  the  light  should  know  with  infallible 
certainty  its  name. 

"  As  stated  in  a  former  report,  I  look  in  great  part  to  the 
flexibility  with  which  gas  lends  itself  to  the  purposes  of  a 
signal-light  for  its  future  usefulness. 

*  It  has  been  calculated  that  the  actual  number  of  possible  gradations 
is  155,  although  in  practice  not  more  than  fifteen  would  probably  be 
made. 


174  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

"  It  may  be  beaten  iii  point  of  cheapness  by  the  mineral- 
oil  now  coming  into  use,  (that  is  to  be  proved  ;)  but  in  point 
of  handiness,  distiuctiveness,  and  power  of  variability  to 
meet  the  changes  of  the  weather,  it  will  maintain  its  supe- 
riority over  all  oils." 

WIGHAM'S  GAS-GUN  FOR  FOG-SIGNALS. 

Gas-gun  for  use  Mr.  Wighain  has  also  invented  a  gas-gun,  to  be  used  as 
-signal.  a  f0g_sjgnaj  at  Cations  illuminated  by  gas  5  and  I  had  an 
opportunity  of  testing  it,  both  at  the  manufactory  in  Dub- 
lin and  at  Howth  Baily  light-station.  Captain  Hawes 
kindly  directed  that  the  gun  should  be  fired  during  our 
observation  of  the  triform-light  from  Kingstown,  so  that,  at 
a  distance  of  six  miles,  I  could  judge  of  its  efficiency  as  a 
signal. 

construction  of  The  gun  is  simply  a  tube  of  iron  connected  with  the  gas- 
holder by  a  halt-inch  pipe;  in  fact,  in  these  experiments  the 
guns  were  nothing  more  than  pieces  of  ordinary  gas  or 

charge.  water-pipe  of  different  diameters.     The  charge  of  the  gun 

is  a  mixture  of  oxygen,  coal-gas,  and  common  air,  one- 
fourth  of  the  mixture  being  common  air  and  the, remainder 
composed  of  equal  volumes  of  oxygen  and  ordinary  illu- 
minating gas. 

Manner  of  fill-  The  proper  quantities  of  the  gases  are  allowed  to  flow 
mg  the  gun.  from  their  respective  reservoirs  into  a  holder,  and  the  mix- 
ture is  thence  transferred  to  the  closed  end  of  the  pipe  or 
breech  of  the  "gun,'7  the  flow  being  regulated  by  a  stop- 
cock. The  mixture  is  lighter  than  common  air,  and  when 
it  fills  the  feed-pipe  and  gun,  the  latter  being  lower  than 
the  source  of  supply,  it  will  remain  charged  or  full  until 
tired,  which  may  be  done  by  touching  a  match  to  an  orifice 
at  any  point  of  the  connecting-pipe  desired,  taking  care 
that  communication  with  the  holder  is  closed  by  the  stop- 
cock. 

Product  of  the  The  product  of  the  explosion  is  carbonic  acid  gas  and 
water,  and,  as  the  latter  would  rapidly  fill  any  part  of  the 
feed-pipe  which  might  be  lower  than  the  gun,  it  would 
probably  be  a  fatal  objection  to  the  use  of  the  invention 
which  immediately  suggests  itself,  viz,  its  application  as  a 
fog- signal  on  outlying  rocks  difficult  to  approach  or  nearly 
submerged.  The  defect  is  all  the  more  to  be  regretted,  as 
it  is  at  precisely  these  points  that  fog-signals  are  most 
needed  and  the  erection  of  other  kinds  is  impracticable. 

At  Mr.  Wigham's  extensive  works  at  Dublin  the  feed- 
pipe was  several  hundred  feet  long. 


oo, 


n 

li 

O  V) 


a 

00. 


n 


°; 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  175 

The  use  of  the  gun  at  any  gas-light  station  would  be    simplicity   of 

the  signal. 

extremely  simple,  and  the  keeper  need  not  go  to  the  gun 
itself,  but  could  easily  fire  it  from  his  watch-room  at  the 
required  intervals.  I  do  not  know  that  the  experiment  has  Suggestion  that 

the  gun  might  be 

even  been  tried,  but  it  will  readily  be  seen  that  by  using  fired  by  electric 
the  electric  spark  the  service  of  the  gun  might  be  made 
still  easier,  for  a  system  of  clock-work  connected  with  a 
battery  could  be  easily  devised  by  which  an  electric  circuit 
could  be  formed  and  a  spark  produced  at  any  desired  in- 
terval, and  thus  the  gun  be  fired  without  any  attention  on 
the  part  of  the  keeper  except  what  might  be  required  to 
keep  the  apparatus  in  order. 
At  Howth  Baily  the  guns  were  twelve  inches  in  diameter    Description  of 

guns   at    HowtQ 


and  from  six  to  nine  feet  long.    The  latter  were  duplicated, 

and  consisted  of  two  connected  pipes,  fired  simultaneously. 

Near  at  hand  the  reports  seemed  loud  and  clear,  but  whenlo^ear    reP°rt 

heard  from  Kingstown  a  high  wind  prevailed  over  Dublin 

Bay,  and  I  was  disappointed  in  the  results.    It  is  true  that 

the  distance  was  six  miles,  and  a  comparison  with  other 

signals  would  have  been  more  satisfactory,  but  I  fancied     superiority  of 

that  the  18-pounder  fog-signal  gun  at  North  Stack,  on  the  gune  at8  North 

other  side  of  the  channel,  would  have  been  more  distinctly  st 

heard  under  the  same  circumstances. 

The  flash  from  this  gun  is  said  to  illuminate  fog  much    illumination 
better  than  that  from  a  gunpowder-gun.  S^6 

I  have  no  doubt  of  the  utility  of  the  invention  for  fog 
signals  at  stations  illuminated  by  gas,  if  the  very  great 
expense  attending  the  manufacture  of  oxygen  can  be  over- 
come; and,  as  Professor  Tyndall  is  now  charged  by  the 
Board  of  Trade  with  the  conduct  of  a  complete  series  of  ex- 
periments with  the  gas-gun,  it  is  to  be  hoped  that  the  in- 
ventive genius  of  Mr.  Wigham  will  overcome  all  objections 
to  which  it  may  now  be  subject. 

In  concluding  my  observations  on  Irish  lights  I  must  ex- 
press sincere  thanks  to  the  commissioners  and  to  Captain 
Hawes,  the  very  intelligent  inspector  of  lights,  as  well  as 
to  Mr.  Lees,  the  secretary  of  the  board,  and  to  Mr.  Wigham, 
for  the  pleasure  and  instruction  I  derived  during  my  limited 
sojourn  in  Ireland. 

SCOTTISH  LIGHTS. 

From  Dublin  I  proceeded  to  Belfast  by  rail  ;  thence  by 
steamer  to  Glasgow,  and  by  rail  again  to  Edinburgh. 
Immediately  on  my  arrival  I  called  at  the  office  of  the  Com-  Visit  to  Com- 

missioners        of 

missiouers  of  Northern  Lights,  and  introduced  myself  to  Mr.  Northern  Lights 


176  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Alexander  Cunningham,  for  many  years  the  secretary  of 
the  Commission,  who  received  me  with  great  cordiality,  and 
with  whom  I  had  an  interesting  conversation  concerning 
the  Scottish  system  of  light-house  administration,  and 
especially  in  regard  to  the  appointment,  payment,  and  regu- 
lations affecting  the  keepers  of  the  northern  lights.  The 

Regulations,  regulations  are  quite  severe,  and  for  any  neglect  of  duty  or 
other  misconduct  the  keeper  is  peremptorily  dismissed  or 
otherwise  punished,  and  a  printed  circular,  advising  keepers 
of  the  facts  in  the  case,  is  at  once  sent  to  all  the  stations  in 
the  service.  The  warnings  thus  received  tend  greatly  to 
promote  the  efficiency  and  good  management  of  the  lights. 
The  following  extracts  from  the  regulations  of  the  Scot- 
tish light-house  service  will  give  an  idea  of  the  great  care 
that  is  taken  to  promote  the  interests  of  the  keepers  and 
to  secure  efficient  lights. 

Appointment  of  All  light-keepers  are  appointed  by  the  Board,  after  an 
examination  in  reading,  writing,  and  arithmetic,  and  a  pro- 
bation of  three  months'  instruction  at  light-houses,  (viz,  six 
weeks  in  a  dioptric  or  lens  light-house,  and  six  weeks  in  a 
catoptric  or  reflector  light-house.) 

instruction  of     While  on  probation  the  a  expectant "  is  carefully  instructed 
keeper!.0 tant   by  ^e  principal  keeper  of  the  light-house  where  he  is  as- 
signed, cautioned  as  to  the  responsibility  he  is  undertaking, 
and  the  invariable  rule  of  the  board,  that  if  he  goes  to  sleep 
at  his  post  he  cannot  be  admitted  into  the  service. 

He  is  specially  instructed  in  the  management  of  the  lamp, 
cleaning  the  lenses  and  mirrors,  and  in  taking  apart  and 
re-adjusting  the  various  machinery.  He  makes  the  monthly 
returns,  and  keeps  the  books  of  the  station  while  there. 
At  the  expiration  of  his  term  of  instruction  the  principal 
keeper  certifies  to  his  competency,  or  gives  reasons  for  not 
doing  so.  If  found  competent,  he  is  appointed  when  a 
vacancy  occurs. 

The  following  are  the  ordinary  rates  of  pay  allowed  to 
keepers : 


Term  of  service. 

Principal 
keeper. 

Assistant 
keeper. 

Under  5  years'  service  .  

Per  annum. 
£56,  ($260) 

Per  annum. 
£44  ($220) 

Abnvpi  5  and  under  10  years'  service 

£58  ($590) 

£46  ($230) 

A  br>vp  1  0  years'  service                                . 

£62,  ($310) 

£48,  ($240) 

Additional  pay  is  given  for  rock  and  other  detached  sta- 
tions, in  some  cases  as  much  as  £20  ($100)  per  year. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


177 


Pensions. 


Each  keeper  has  a  furnished  house,  with  annual  supplies  of   Dwelling    and 
coal  and  oil,  and  where  no  land  is  attached  to  the  station  an  ai 
allowance  of  £10  (-$50)  per  annum  is  made.     They  have  also 
an  allowance  for  washing  and  for  expenses  when  traveling 
on  public  service.    They  are  uniformed  at  public  expense. 
Three  pounds  ($15)  per  annum  is  retained  from  the  salaries 
of  each  and  applied  toward  effecting  an  insurance  on  their 
lives. 

Retiring  pensions  are  allowed,  and  gratuities  if  they  are 
constrained  to  quit  the  service  before  being  entitled  to  a 
pension  by  reason  of  injury  sustained  in  the  discharge  of 
duty  or  from  other  infirmity  of  mind  or  body. 

The  ground  attached  to  light-houses  is  carefully  culti- 
vated and  turned  to  the  best  account,  and  the  growing  crops 
are  transferred  when  one  keeper  relieves  another. 

Light -keepers  at  rock-stations  are  allowed  daily  rations, 
as  follows : 

One  pound  of  butcher-meat. 

One  pound  of  bread. 

Two  ounces  of  oatmeal. 

Two  ounces  of  barley. 

Two  ounces  of  butter. 

One  quart  of  beer. 

Vegetables  when  procurable. 

For  tea,  sugar,  salt,  and  other  table  necessaries,  4rf.  per  day. 

The  light-houses  are  arranged  in  groups,  and  each  group 
is  supplied  with  a  moderate  amount  of  current  literature 
and  periodicals,  which  circulate  in  the  group,  remaining  a 
specified  time  at  each  station,  and  afterward  are  bound  and 
form  part  of  the  library  of  the  last  station.  Each  light-house 
is  in  turn.the  last  of  ics  group,  so  as  to  give  each  station  its 
fair  share  of  books.  The  Weekly  Scotsman  and  the  Il- 
lustrated London  News  are  sent  to  each  light-house. 

An  ordained  clergyman  of  the  Church  of  Scotland  is  ap- 
pointed to  visit  annually  those  remote  stations  where  keep- 
ers and  their  families  cannot  attend  divine  worship.  He 
remains  about  two  weeks  at  each  station  conducting  divine 
service  and  instructing  the  children  at  the  station  in  ordi- 
nary branches  of  education  as  well  as  in  their  religious  duties 

It  is  recommended  by  the  Commissioners  that  each  light- 
keeper  or  his  wife  spend  some  time  daily  teaching  their 
children  after  the  clergyman  leaves,  and  when  he  returns 
the  following  year  he  examines  the  children  as  to  their  pro- 
gress. 

Medical  attendants  are  also  appointed  for  remote  stations, 
S.  Ex.  54 12 


Libraries. 


Attendance   of 
clergyman. 


Medical  attend- 
ants. 


178  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

and  are  allowed  a  fixed  sum  per  annum,  exclusive  of  the  fees, 
paid  by  the  keepers. 

They  are  to  attend  on  the  keepers,  who  pay  them  a  fixed 
fee  for  each  visit.  Medicines  and  medical  instructions  are 
furnished  each  station. 

Report  or  quai-     Keepers  are  required  to  report  annually  the  quality  of  the 

ce!ved.8t<  esre~  stores  received  after  a  trial  of  them  in  detail.    A  special. 

Test  of  oil.       tr|a]  ig  ma(je  Of  the  Oii  for  ten  nights  from  December  1  to  10  ; 

the  result  of  each  night's  trial  is  noted  on  a  for.n  prepared 
for  that  purpose  and  finally  reported  to  the  Board, 
p  recant  ions     Special  precaution  s  are  taken  with  mineral-oil.     The  tanks 

with  mineral-oil. 

have  tight-fitting  covers,  and  the  oil  is  tested  in  the  presence 
of  the  keepers  to  ascertain  that  theflashing-pointis  not  below 
120°  Fahrenheit.  In  addition  to  this  the  keeper  is  required 
to  test  it  before  commencing  to  use  out  of  a  new  tank. 

Appointment  of  For  each  station  a  person  resident  near  the  light-house  is 
iightkeepers.a  appointed  an  "occasional  "  light-keeper,  and  is  required  to 
attend  the  station  whenever  required  by  the  regular  keepers. 
They  are  regularly  trained,  are  under  the  supervision  of  the 
commissioners,  and  are  allowed  regular  rates  for  each  day's 
attendance  at  the  station.  They  are  obliged  to  attend  the 
light  at  least  twenty  nights  per  annum  in  order  to  keep  in 
practice. 

Boatman  for  At  each  island-station  a  boatman  is  appointed  and  paid 
either  a  fixed  salary  per  annum 'or  a  certain  rate  per  trip, 
and  when  he  has  no  boat  of  his  own,  the  Commissioners 
furnish  one.  He  is  obliged  to  make  at  least  four  trips  to 
the  light-house  every  month,  and  to  visit  it  whenever  sig- 
naled. 

sketch  of  the  The  "Board  of  Commissioners  for  Northern  Lights"  was 
om"established  in  1798.  Up  to  that  time  the  Trinity  House 
exercised  direct  control  over  the  Scottish  lights,  and  it  does 
so  now  in  some  small  degree.  The  Commissioners  receive 
no  salary.  They  are  all  ex-officio  members,  viz,  the  Lord- 
Advocate  and  Solicitor-General  of  Scotland,  the  chief  mu- 
nicipal authority  (whether  Lord  Provost  or  Senior  Bailie) 
of  Edinburgh,  Glasgow,  Aberdeen,  Inverness,  Campbell- 
town,  Dundee,  Leith,  and  Greenock,  and  the  sheriffs  of  the 
maritime  counties  of  Scotland.  The  committees  of  the 
Board  meet  twice  a  month,  but  the  entire  executive  func- 
tions are  exercised  by  the  secretary  and  engineers. 

The  latter  are  Messrs.  David  and  Thomas  Stevenson, 
whose  published  writings  on  light-houses  and  their  illumi- 
nation have  not  only  given  them  a  world-wide  fame,  but 
have  established  the  reputation  of  the  light-house  system 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  179 

of  Scotland  as  second  to  none  bat  that  of  France,  which  is 
acknowledged  to  be  the  model  for  all  others. 

Both  were  unfortunately  absent  the  first  morning  I  called, 
and  I  took  the  opportunity  of  seeing  somewhat  of  Edin- 
burgh, which,  I  think,  is  justly  called  the  most  picturesque 
city  of  Europe. 

As  I  found  I  would  have  sufficient  time,  I  made  a  quick 
journey  to  Stirling  Castle,  Loch  Lomond,  Loch  Katrine,  and 
the  Trossachs.  On  my  return,  I  had  the  pleasure  of  meet- 
ing Mr.  Thomas  Stevenson,  and  had  a  prolonged  and  inter- 
esting conversation  with  him,  gathering  much  information 
on  subjects  connected  with  the  object  of  my  visit.  He 
showed  me  a  reflector  for  light-houses,  which  was  made 
after  designs  of  his  grandfather  nearly  a  century  ago.  The 
interior  reflecting-surface  is  composed  of  little  facets  of 
mirror-glass  set  into  a  paraboloidal  form,  and  it  is  appar- 
ently as  bright  and  useful  to-day  as  when  it  was  new,  show- 
ing that  such  reflectors,  which  suffer  no  wearing  of  the  sur- 
face by  polishing,  are  very  durable.  In  the  opinion  of  Mr. 
Stevenson  the  silvered  copper  reflectors,  which  depend  for 
their  efficiency  on  the  polish  given  them  by  the  keepers, 
are  really  no  improvement,  they  having  no  advantage  over 
those  previously  used.  Mr.  Stevenson  has  invented  a  new 
form  for  harbor  and  ships7  lights,  which  he  calls  the  differ-  Differential  re- 
ential  reflector,  in  which  the  vertical  sections  are  parabolic 
and  the  horizontal  elliptical ;  and  he  showed  me  a  model. 
None  of  this  kind,  however,  had  been  made  for  service. 

He  also  showed  me  models  illustrating  the  use  of  dioptric 
lights  in  light-ships ;  also  his  holophote,  hemispherical  diop- 
tric mirror  of  total  reflection,  and  holophone  or  sound  re- 
flector.   The  latter  is  shown  in  Figs.  20  and  21,  and  Mr.    stevensou'H 
Stevenson  kindly  promised  to  send  me  a  model  of  the  lat-  sound-reflector. 
ter  as  soon  as  the  mechanics  employed  by  the  Board  could 
find  time  to  make  it,  (I  have  since  learned  that  it  is  en  route, 
having  been  sent  according  to  promise,)  so  that  from  it  a 
fog-signal  reflector  can  be  made  for  actual  trial  in  our 
experiments. 

In  regard  to  reflectors  for  fog-signals,  Mr.  Stevenson  con- 
firmed the  opinion  entertained  by  Professor  Henry,  that  if 
they  are  of  metal  they  should  be  covered  with  plaster  or 
some  other  substance  to  prevent  vibration;  also,  that  wooden 
surfaces  would  be  as  efficient  reflectors  as  any  others.  This 
would  enable  us  to  construct  a  holophone  cheaply  and  ex- 
peditiously,  if  it  should  be  desired  to  use  one  in  our  experi- 
ments. 


180 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Mr.  Stevenson  is  the  inventor  of  several  important  modi- 
fications in  the  form  of  dioptric  apparatus  for  light-houses, 
and  at  the  time  of  my  visit,  the  Northern  Lights  Board  oc- 
cupied a  large  space  in  the  industrial  exhibition  at  Edin- 
burgh, having  an  exceedingly  full  and  interesting  display 
of  illuminating-apparatus,  and  of  models  of  some  of  Scot- 
land's famous  light-houses,  including  Skerryvore  and  the 
Bell,  or  Inch  Cape  Eock.  Among  other  interesting  objects 
Apparatus  for  I  noticed  a  fixed  azimuthal  condensing-apparatus,  designed 

fintre-liffhts.  ,,       ,,  ,        ,.          „ 

for  "  leading,"  or,  as  we  say, "  range"  lights,  for  the  river  Tay. 
It  collects  the  rays  of  the  lamp  and  distributes  them  equally 
over  an  angular  space  of  45°,  and  combines  for  this  purpose 
five  optical  agents,  viz,  Fresuel's  fixed  light-apparatus,  Ste- 
venson's condensing  prisms,  a  half  holophote,  right-angled 
conoid al  prisms,  and  a  hemispherical  mirror  of  totally  re- 
flecting prisms. 

Fig.  20. 

Fig.  21. 


range-lights. 


Vertical  section  of  holophone.  Front  elevation  of  holophone. 

There  was  also  on  exhibition  a  model  of  a  light-house 
ot  Mr.  stevenson.  lantern  with  diagonal  sash-bars,  the  placard  of  which  stated 
that  the  first  lantern  of  that  description  was  constructed 
by  Mr.  Stevenson  in  183G. 

Mr.  Stevenson  remarked,  in  regard  to  fog-signals,  that 
the  Board  have  none  operated  by  steam,  but  that  bells  are 
placed  wherever  they  are  useful.  The  only  instance  in 
Scotland  of  a  steam  oi1  hot-air  fog-signal  is  in  the  river 
Clyde,  and  it  is  maintained  by  a  steamship  company ;  yet 
the  coasts  of  Scotland  are  habitually  foggy  at  some  seasons 


Diagonal  sash- 
bars  ail  invention 


Fog-signals. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  181 

of  the  year,  being,  I  infer,  as  unfortunate  in  this  respect  as 
our  northern  Atlantic  or  our  Pacific  coasts. 

Neither  have  the  Scottish  Board  any  light-ships,  nor  in- 
deed  is  there  any  occasion  for  them,  the  coast  being  every- 
where abrupt  with  no  outlying  shoals  or  reefs.  Mr.  Steven- 
son gave  as  his  opinion,  derived  from  observations,  that  re- 
volving lights  should  be  used  as  much  as  practicable  for 
light-ships,  for  the  reason  that  they  have  a  greater  range  of 
visibility  than  fixed  lights. 

Messrs.  Stevenson  and  Cunningham  confirmed  the  state-  Adoption  of  the 
ment  made  to  me  by  Captain  Doty  in  London,  viz,  that  the  P^1^^ 
mineral  oil  lamp  invented  by  the  latter  had  been  adopted  Jj^J.0  Board  ot> 
by  the  Scottish  Board,  subject  to  the  approval  of  the  Board 
of  Trade,  and  with  the  understanding  that  he  should  receive 
as  remuneration  for  his  patent  the  saving  effected  in  one 
year  at  each  light-house  where  it  might  be  introduced.  At 
the  time  of  my  visit,  however,  it  had  been  actually  intro- 
duced into  but  five  light-houses,  as  the  Board  of  Trade  hesi- 
tated at  the  terms  of  Doty's  offer,  which  would  give  him 
for  the  use  of  his  patent  about  £75  ($375)  for  each  first- 
order  light-house,  and  proportional  amounts  for  smaller 
lights.  The  Board  of  Trade,  acting  under  the  advice  of 
Trinity  House,  directed  that  the  substitution  of  mineral  for 
colza  oil  in  Scotch  light-houses  should  be  deferred  until  the 
experiments  on  the  relative  values  of  the  Trinity  House 
(Douglass)  and  the  Doty  lamps  should  be  completed;  in 
order,  I  presume,  to  avoid  paying  a  royalty  to  Doty  if  the 
Douglass  lamp  should  be  found  superior  or  equal  to  his.* 

In  this  connection  I  quote,  from  a  parliamentary  paper    Extracts  from 
in  my  possession,  the  following  extracts  from  a  report  made  ifessrsrepsteve°n- 
in  1870,  before  the  adoption  of  mineral-oil  in  British  light- so 
houses,  by  the  Messrs.  Stevenson,  engineers  of  Scottish 
lights : 

»'lst.  The  paraffine-flame  produced  by  the  four-wick  me-    Flame  pro 
chanical  lamp  is  2^  inches  in  height,  and  of  great  purity  fi£e?d  by  par 
and  intensity. 

"  2d.  There  is  no  difficulty,  or  even  trouble,  in  maintain-    carenecessary 
ing  the  flame. 

"  3d.  According  to  those  in  charge,  the  light  is,  on  the 
whole,  more  easily  attended  to  than  that  from  colza-oil. 

a  4th.  The  same  wicks  have  been  used  throughout  the    wicks, 
whole  thirty  days7  experiments,  and  are  still  quite  fit  for  use. 

*  The  Board  of  Trade  have  since  given  its  authority  for  the  substitu- 
tion of  mineral-oil  in  all  of  the  Scottish  light-houses. 


182  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

Lamp-glass.         "  5th.  The  lamp-glass  used  for  the  experiments  has  stood 

during  the  month  without  breakage. 
ventilation.         "  6th.  The  ordinary  ventilation  of  the  light-room  has  been 

found  quite  sufficient. 
Absence  from     "  7th.  No  inconvenience  has  occurred  from  smoking  of 

the  wick  or  smell  of  the  paraffine, 


intem-     u  8th.  No  undue  rise  of  temperature  of  the  light-room  or 

perature  of    the  ,  , 

loom.  apparatus  has  occurred. 

Temperature  of  u  9th.  The  temperature  of  the  paraffine  in  the  cistern  of 
lamp  did  not,  after  twelve  hours'  burning,  rise  above  from 
about  55°  to  63°. 

Fiashing-point.  "  10th.  The  safe  vaporizing  temperature,  or  that  to  which 
Young's  paraffine  may  be  heated  without  giving  inflammable 
vapor,  as  tested  by  us  with  Mr.  Kowat's  patent  instrument, 
is  about  140°. 

Quantity  con-     u  llth.  The  quantity  of  paraffine  consumed  in  the  first- 
sumed.  order  light  was  at  the  rate  of  718  gallons  per  annum.    The 

consumption  of  colza-oil  is  about  800  gallons  per  annum. 
******  * 

Cost  "  Taking  the  cost  of  colza-oil  at  34s.  per  cwt.,  (2s.  9d.  'a 

gallon,  68|  cents,)  which  was  the  price  in  1869,  adopted  in 
our  recent  reports  on  illumination  by  gas,  and  paraffine  at 
its  present  price  of  Is.  4d.  (33  J  cents)  per  gallon,  we  find 
that  the  cost  of  maintaining  a  first-class  light  with  colza 
and  paraffiue  will  be  £110  ($550)  and  £47  17s.  4d,  ($239.33  J) 
respectively,  thus  giving  a  yearly  saving  on  each  first-class 
light  of  £62  2s.  Sd.,  ($310.66§  ;)  but  if  we  take  the  present 
contract  rate  of  colza  of  38s.  M.  per  cwt.,  (3s.  Id;  per  gal- 
lon, 77  cents,)  the  saving  would  amount  to  £75  9s.  4$., 
($377.33J.)  On  the  supposition  of  paraffiue  being  used  for 
all  the  lights  under  the  charge  of  the  commissioners,  the 

Annual  saving.  saving,  calculated  on  the  same  basis,  would  amount  to  about 
£2,874  ($14,370)  per  annum,  but  at  the  present  contract 
rate  of  colza  the  saving  would  amount  to  £3,478  15s.  Id. 

($17,393.89£)  per  annum. 

*  *  -  *  *  *  *  * 

"We  have  perfect  confidence  in  recommending  the  use  of 
paraffine  for  light-house  illumination.  Its  introduction 
would  require  to  be  clone  gradually;  the  light-keepers 
would  require  to  receive  some  instructions  in  its  use,  and  a 
slight  alteration  would  in  each  case  require  to  be  made  on 
the  level  of  the  burner  with  reference  to  the  optical  axis  of 
the  apparatus,  and  the  marks  for  testing  the  adjustment  of 
the  lamp  to  be  carefully  altered.  A  full  set  of  directions 
would  also  require  to  be  drawn  up  and  furnished  to  all  the 
stations  when  the  change  is  made." 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  183 

Ko  more  convincing  proof  of  the  utility  of  permanence    Good  results  of 

permanence      in 

in  the  peculiar  service  of  light-bouse  administration  can  be  fight-bouse  sen- 
given  than  the  excellent  reputation  the  Scottish  lights  bearic( 
throughout  the  world  for  economy  and  efficiency,  and  it  is 
well  known  that  the  Commissioners  are  eager  to  adopt  any 
improvement  which  tends  to  the  increase  of  either.    Mir. 
Cunningham  has  for  many  years  most  ably  filled  the  posi- 
tion of  secretary,  and  for  nearly  a  hundred  years  the  Ste- 
venson family  has  supplied  engineers. 

The  time  at  my  disposal  was  too  limited  to  allow  me  to 
visit  any  of  the  Scottish  light-houses,  and  I  especially  re- 
gretted that  I  could  not  accept  Mr.  Stevenson's  invitation 
to  visit  Bell-Bock  light-house.  My  thanks  are  due  both  to 
Mr.  Thomas  Stevenson  and  Mr.  Cunningham  for  their  polite 
attentions  while  I  was  at  Edinburgh. 

THE  MANUFACTORY  OF  DIOPTRIC  APPARATUS  FOR  LIGHT- 
HOUSES OF  CHANCE  BROTHERS  AND  COMPANY,  NEAR 
BIRMINGHAM. 

On  my  return  to  London  from  Edinburgh  I  visited  the 
extensive  glass-works  of  Chance  Brothers  &  Company  at 
Spon  Lane,  near  Birmingham,  in  compliance  with  an  invi- 
tation which  I  received  from  Mr.  J.  T.  Chance  soon  after 
arriving  in  England.  This  establishment  is  most  extensive, 
and  is  mainly  devoted  to  the  manufacture  of  plate-glass, 
which  is  sent  from  here  to  all  parts  of  the  world. 

A  part  of  the  works  is,  however,  devoted  exclusively  to 
the  manufacture  of  apparatus  for  light-houses,  a  manufac- 
ture commenced  by  this  firm  in  1855,  in  competition  with 
the  lens-makers  of  Paris,  who  until  that  date  monopolized 
this  branch  of  industry. 

Mr.  Chance  stated  that  in  establishing  this  part  of  their 
trade  they  had  lost  more  than  $100,000,  but  that  their  rep- 
utation  is  now  established,  and  they  supply  not  only  Great 
Britain,  but  many  other  countries,  with  lenses,  lanterns, 
lamps,  and  accessories  of  all  kinds  necessary  for  the  service 
of  lights. 

They  have  in  use  a  great  variety  of  machines  for  grinding    Machines  for 

,         ..    ,  .         ^,  .  polishing  prisms. 

and  polishing  the  prisms,  and  the  establishment  appears  to 
be  as  complete  in  every  particular  as  any  which  1  saw  at 
Paris. 

The  scientific  branch  of  this  industry  is  in  charge  of   Dr. 
Dr.  Hopkinson,  who  is  responsible  not  only  for  the  cor- 
rectness of  the  forms  of  the  various  parts  of  every  optical 
apparatus,  but  for  their  correct  assembling,  and  he  person- 
ally tests  each  lens  before  it  leaves  the  manufactory-. 


184  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Flashing-lens  Among  other  works  in  hand,  I  saw  a  revolving  lens  of  the 
first  order  for  the  light-bouse  at  Start  Point,  on  the  coast  of 
Devonshire,  remarkable  for  having  flash-panels  that  cover 
arcs  of  60°,  which  is  larger  than  any  before  attempted,  as 
far  as  I  am  informed.  Heretofore  the  arcs  of  first-  order 
lenses  have  not  extended  45°,  and  as  the  amount  of  light  in 
the  flashes  is  nearly  in  proportion  to  the  size  of  the  panels, 
it  follows  that  the  power  of  this  lens,  when  compared  with 
those  of  similar  character  heretofore  made,  is  nearly  as 
3  to  2. 

Eed  cut  to  be  A  red  cut  showing  the  position  of  outlying  rocks  near 
Start  Point,  will  be  produced,  as  is  done  at  the  electric  lights 
at  Souter  Point,  by  collecting  a  portion  of  the  rear  light  and 
throwing  it  down  a  tube  to  a  lower  light-room  upon  a  set  of 
totally  reflecting  prisms,  which  in  turn  bends  the  beam  and 
turns  it  out  upon  the  sea. 

Apparatus  for     A  new  first-order  dioptric  apparatus  for  Longships  light- 
hoShips  light'  house,  on  the  coast  of  Cornwall,  was  also  in  progress,  and  I 
had  the  pleasure  of  witnessing  Dr.  Hopkiuson's  final  test 
of  the  accuracy  of  this  lens. 

^octor  a^so  kindly  presented  me  with  a  photometer, 


Dr     HO  M 
sou's  photometer,  of  his  own  invention,  for  comparison  of  lights  at  a  distance, 

which  is  designed  to  be  free  from  the  defects  inherent  in 
those  depending  on  absorption. 

It  is  very  compact,  and  consists  of  two  Nicol  prisms, 
which  can  be  moved  relatively  to  each  other  in  azimuth.  A 
little  tube  carries  both  the  analyzing  prism  and  a  second  tube 
containing  the  polarizing  prism.  The  latter  being  turned 
till  the  light,  which  is  viewed  through  the  axis  of  both 
prisms,  is  eclipsed,  the  angle  through  which  the  polarizer  is 
moved,  is  read.  The  other  light  being  then  observed  in  the 
same  way,  a  comparison  of  the  angles  gives  the  relation  of 
the  powers  of  the  lights. 

For  many  years  the  place  now  occupied  by  Dr.  Hopkin- 
son  was  filled  by  Mr.  J.  T.  Chance  himself,  and  to  him  the 
service  of  light-house  illumination  is  indebted  for  several 
treatises  on  the  subject. 

THE  LIGHT-HOUSES  OF  FBANCE. 

THE  COMMISSION  DES  PHARES. 

I  arrived  at  Paris  on  Saturday,  the  5th  of  July,  and  on 

the  7th  I  went  to  the  offices  of  the  Commission  des  Pliares,  or 

Light-House  Board  of  France,  situated  on  the  hill  Trocadero, 

which  overlooks  the  Seine  and  the  Champ  de  Mars.    This 

nfuse  Boardisllt'  Board  is  composed  as  follows  :  Four  engineers,  two  naval 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  185 

officers,  one  member  of  the  institute,  one  inspector- general 
of  marine  engineers,  one  hydrographic  engineer. 

Tbe  executive  officers  of  the  establishment  at  Paris  are 
M.  Leonce  Reynaud,  Inspector-General  of  the  Corps  of  En-  " 
giueers  des  Fonts  et  Chaussees,  who  is  Director  of  the  French 
light-house  administration,  and  M.  Allard,  engineer  of  the 
same  corps,  and  Eugineer-m-Chief  and  Secretary  to  the 
Commission. 

The  entire  administration  on  the  seaboard  is  in  the  nandsm^i|JJa1^ead- 
of  the   engineers,  who,  in   addition   to  other    duties,  are 
charged  with  the  work  of  river  and  harbor  improvements. 

At  the  time  of  my  visit  to  the  Depot  des  Phares,  M.  Rey- 
naud,  who  is,  I  believe,  much  occupied  with  other  duties, 
especially  at  the  Ecole  des  Ponts  et  Chausxees,  wras  absent, 
but  I  had  the  pleasure  of  meeting  M.  Allard,  upon  whom 
the  major  part  of  the  executive  duties  devolves. 

During  my  long  interview  with  M.  Allard,  he  kindly 
showed  me  the  different  parts  of  the  establishment  at  Tro- 
cadero,  all  of  much  interest,  particularly  the  grand  hall  or 
council-chamber  of  the  Commission,  the  museum,  the  experi- 
mental rooms,  and  store-rooms. 

The  buildings  are  placed  around  a  rectangular  court-yard    i>  6  p  6 1  des 
in  which  are  models  of  light-houses,  buoys,  &c. 

The  principal  building,  which  contains  the  offices  of  the 
commission,  is  a  handsome,  structure  150  feet  long  and  two 
stories  in  height,  built  of  brick  and  limestone  in  alternate 
courses.  It  is  surmounted  by  a  towTer  and  a  first-order  Ian-  Tower  for  exi 
tern,  where  experiments  are  made,  and  from  which  a  mag- Periments- 
neto-electric  light  is  exhibited  on  occasions  of  public  dis- 
play ;  as,  lor  example,  the  fete  nocturne  in  the  Champ  de 
Mars,  ill  honor  of  the  Shah  of  Persia.  This  fete  M.  Allard 
was  kind  enough  to  invite  me  to  witness  from  the  Depot 
des  Phares,  which  afforded  a  most  desirable  site  from  which 
to  view  the  magnificent  spectacle. 

The  grand  entrance  hall  also  contains  many  models,  and 
those  of  the  rock  light  houses  of  France  at  once  arrest  the 
attention  of  the  visitor. 

The  council-chamber  of  the  commission  is  richly  decorated,     council  cham- 
and  upon  its  walls  are  painted  two  large  charts,  each  occu-ber' 
pying  an  entire  side,  one  of  the  world,  on  Mercator's  projec- 
tion, showing  all  the  lights  now  in  existence,  thus,  as  M. 
Allard  happily  observed,  marking  the  progress  of  civiliza- 
tion in  a  most  striking  manner.    The  other  chart  was  one 
of  France,  showing  not  only  its  lights,  but  the  illuminated 
areas. 


186  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

A  bust  of  Augustin  Fresnei,  engineer  of  Fonts  et  Chans- 
sees,  the  first  Secretary  of  the  Commission,  and  the  invent- 
or of  the  system  of  lights  which  now  illuminates  the  coasts 
of  most  countries  of  the  globe,  occupies  a  prominent 
place,  not  only  here,  but,  as  I  found  afterward,  at  all  French 
light-stations,  similar  ones  being  placed  over  the  entrance- 
Museum,  doors  at  each  station  I  visited.  The  museum  contains  all 
kinds  of  illuminating  apparatus,  both  dioptric  and  catop- 
tric, though  the  latter  is  not  now  used  in  any  French  light- 
house. 

The  collection  of  dioptric  apparatus  embraced  many  arti- 
cles of  historical  interest,  among  which  I  was  shown  the 
first  lens  made  from  the  designs  of  Augustin  Fresnei,  which 
was  placed  in  the  Tour  de  Oordouan,  and  various  apparatus 
showing  the  successive  steps  by  which  he  arrived  at  the 
lens  which  is  now  used  in  all  parts  of  the  world. 
Haii.  The  hall  also  contains  models  of  buoys  and  beacons. 

French  bell-buoys  have  four  hammers  or  clappers,  and  at 
the  top  of  the  frame  are  placed  small  mirrors  to  catch  the 
eye  of  the  mariner. 

System  of  coi-     A  uniform  system  is  used  for  the  coloring  of  all  the  buoys 
oririg buoys.        and  beacons  of  the  coast  of  France.    All  of  those  marks 

which  should  be  left  by  the  navigator  on  the  starboard  hand 
when  approaching  from  seaward  are  painted  red  $*  those 
which  should  be  kept  on  the  port  side  are  painted  black  ; 
those  which  may  be  left  indifferently  on  either  side  are  paint- 
ed with  horizontal  stripes,  alternately  red  and  black. 

Beacons.  Beacons  are  colored  in  this  way  only  above  high-water 

mark  ;  below  that  level  they  are  painted  white. 

The  red  and  black  are  varied  as  circumstances  may  require 
by  painting  in  white,  design  of  checks,  vertical  bands,  &c. 

color  of  buoys     Buoys  marking  anchors,  &c.,  are  painted  white.    On  each 

marking  anchors.  ,  ..     .  ._  .,  .  ,     .  ..         , 

buoy  or  beacon  is  painted  either  the  entire  or  abridged  name 
of  the  bank  or  rock  that  it  marks,  and  buoys  and  beacons 
belonging  to  the  same  passage  are  numbered  serially,  com- 
btu>y™bcnng  of  mencing  to  the  seaward.  The  even  .numbers  are  given  to 
buoys  and  beacons  which  the  navigator  leaves  on  the  star- 
board hand,  that  is,  to  the  red  ones,  and  the  odd  numbers 
are  given  to  the  black  buoys  and  beacons.  The  buoys  and 
beacons  painted  with  red  and  black  stripes  bear  names,  but 
no  numbers. 

*  The  red  is  soon  tarnished  by  the  sea-water,  and  in  order  to  prevent 
any  error  it  has  been  decided  that  those  marks  which  are  painted  red 
shall  hereafter  have  a  white  crown  a  little  below  their  summit. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  187 

Small  heads  of  rocks  in  frequented  passes  may  be  painted 
the  same  as  the  beacons,  except  that  only  the  most  promi- 
nent part  is  colored  when  they  show  a  surface  larger  than 
is  necessary  for  clear  distinction. 

No  oils  are  kept  at  the  depot,  nor  are  they  tested  there,  as    oils   sent  di- 

rectly      to      the 

they  are  sent  by  the  contractors  directly  to  the  light-houses  light-houses. 

and  there  thoroughly  tested  by  the  engineer  of  the  district. 

Lenses  and  lamps,  however,  undergo  a  thorough  trial  at  the  len869 


depot.     The  photometer  used  is  different  from  Buusen's,    photometers 

used  by  us,  and  instead  of  the  standard  light  and  the  one 

under  test  being  both  fixed  in  position,  the  former  or  unit 

is  moved  until  the  beams,  passing  through  a  slit  or  opening 

in  the  photometer  and  falling  upon  a  pane  of  glass  which 

has  a  ground  surface  or  is  covered  with  a  sheet  of  paper, 

are,  when  viewed  on  the  reverse  side,  equal  in  intensitj*. 

The  distances  from  the  photometer  are  then  measured  by  a 

tape-line,  and  reference  to  a  calculated  table  shows  at  once 

the  intensity  of  the  light  under  test  in  terms  of  the  standard 

or  unit.    This  unit  in  France,  both  in  the  practice  of  the 

officers  of  the  light-house  administration  and  that  of  the 

lens-manufacturers,  is  always  the  Carcel  burner,  consuming 

40  grams  (G1.728  grains)  of  colza-oil  per  hour. 

The  relation  between  the  French  and  English  unit  is  not  Relation  ot 
accurately  known.  I  have  been  informed  by  Mr.  Douglass  French  Vmts'o'f 
1  hat  the  French  unit  is  estimated  by  the  French  and  English 
gas-engineers  as  equal  to  9.6  candles. 

M.  Lepaute  informed  me,  however,  that  it  has  heretofore 
been  considered  equal  to  11  J  caudles.  M.  Lepaute  has  re- 
cently been  desired  by  the  French  government  to  ascertain 
the  exact  relative  value.  M.  Allard  stated  that  the  French 
engineers  prefer  the  Carcel  to  the  candle  unit  used  in 
England  and  the  United  States  on  account  of  greater  vari- 
ability in  power  to  which  the  latter  is  subject  in  consequence 
of  irregularities  in  the  wick. 

I  found  this  photometer  to  be  easily  operated,  and  the 
bringing  into  contact  upon  ^Jie  pane,  the  two  images  of 
the  slit,  seemed  to  me  to  show  with  more  precision  when  the 
desired  equality  of  intensities  of  beams  were  arrived  at  than 
Bunsen's  apparatus. 

M.  Allard  showed  me  the  mode  adopted  by  the  Commis- 
sion for  testing  mineral-oil  in  apparatus  especially  designed 
for  the  purpose,  and  shown  in  Figs.  22  and  23. 

A  box  containing  these  instruments  is  supplied  to  every 
light  where  mineral-oil  is  used.  The  qualities  to  be  tested 
are  the  specific  gravity  and  the  flashing-point.  The  specific 
gravity  is  tested  by  an  areometer,  (see  Fig.  22.) 


188 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Test  for  spe-  The  test-glass  is  filled  with  the  oil  to  be  tested  to  within 
three-quarters  of  an  inch  of  the  edge ;  then  the  areometer 
is  plunged  in  and  the  specific  gravity  is  read  from  it.  The 
standard  required  is  between  .810  and  .820  at  15°  centigrade, 
(59°  Fahrenheit.)  This  temperature  is  obtained  in  winter 
by  heating  the  oil  in  a  water-bath,  and  in  summer  by  cooling 
the  vessel  containing  it  by  means  of  fresh  water.  If  these 
methods  are  not  available  the  specific  gravity  and  tempera- 
ture of  the  oil  are  taken,  and  a  correction  of  .00074  is  added 
for  every  degree  below  15°  centigrade,  or  deducted  for  every 
degree  above. 


Fig.  22. 


Fig.  23. 


Areometer. 


Apparatus  for  testing  the  flashing-point. 


To  test  the  flashing-point  the  instrument  shown  in  Fig. 
23  is  used.  The  oil  to  be  te^ed  is  poured  into  a  little  cop- 
per capsule  placed  in  a  water-bath  heated  by  a  spirit-lamp  5 
a  thermometer  so  suspended  as  to  dip  into  the  oil  gives  the 
temperature.  While  heating,  matches  are  applied  at  short 
intervals  near  the  surface  of  the  liquid.  The  degree  of  the 
thermometer  at  which  ignition  takes  place  is  the  flashing- 
point.  It  is  considered  that  an  oil  is  unsafe  for  illuminating 
purposes  if  it  gives  out  inflammable  vapors  below  50°  centi- 
grade, (122°  Fahrenheit,)  and  the  contracts  require  that  the 
oil  actually  used  shall  not  have  a  flashing-point  lower  than 
600  centigrade,  (140°  Fahrenheit.) 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  189 

The  principal  keepers  of  the  lights  are  required  to  test    oils  tested  by 
the  oil  when  delivered  by  the  contractors.     They  heat  it  in  thekecPers- 
the  capsule  until  the  thermometer  shows  more  than  60° 
centigrade,  then  extinguish  the  lamp,  and  while  the  mer- 
cury slowly  descends  apply  the  match. 

Before  the  introduction  of  mineral-oil  the  colza  oil  for-  coiza-oii  testa 
merly  used  was  required  to  be  of  the  first  quality,  perfectly 
purified  and  clarified.  The  oils  delivered  by  the  contractor 
were  first  tested  by  drawing  a  certain  quantity  from  each 
cask  and  burning  it  in  two  or  three  night-lamps  with  floats. 
The  oil  was  refused  if  the  lamps,  properly  arranged,  went 
out  ot  themselves  before  burning  twelve  hours.  If  they  did 
not  burn  twenty  hours  the  oil  was  considered,  if  not  bad, 
at  least  of  doubtful  quality.  In  this  case,  or  any  other  where 
there  was  doubt,  the  decisive  test  was  to  compare  the  oil  co^c^1ivetestot 
with  colza  known  to  be  of  the  first  quality.  The  oil  to  be 
tested  was  not  considered  acceptable  if,  during  combustion  of 
sixteen  hours,  it  did  not  give  as  good  a  flame,  or  if  it  depos- 
ited more  carbon  on  the  wick  than  did  the  standard  oil,  other 
circumstances  being  equal.  -In  this  comparative  test  either 
ordinary  constant-level  lamps  or  the  regular  light-house 
lamps  were  used. 

In  regard  to  lamps,  M.  Allard  stated  that  the  French  pre-  Lamps  pre- 
fer the  mechanical  lamp,  although  the  "  moderator77  is  used 
in  some  of  the  light-houses,  and  the  constant-level  lamp  in 
others,  but  in  no  case  is  any  part  of  the  lamp  allowed  to 
obstruct  any  portion  of  the  light  when  the  entire  horizon  is 
required  to  be  illuminated.  For  small  orders  (below  the 
fourth)  lamps  in  which  the  oil  is  drawn  up  by  the  capillary 
attraction  of  the  wick  are  used  in  most  cases. 

The  French  are  experimenting  with  a  six-wick  burner, 
but  in  M.  Allard's  opinion  the  heat  generated  would  be 
found  to  be  too  intense  for  the  safety  of  chimneys.  As  1 
have  stated,  the  English  are  using  the  six-wick  burner  in  the 
Douglass  "lamp  of  single  and  double  power"  for  the  pur- 
pose of  producing  a  powerful  flame  in  thick  whether,  but,  as 
far  as  I  am  informed,  the  French  have  not  manufactured  any 
lamps  with  more  than  five  wicks. 

M.  Allard  confirmed  Mr.  Douglass's  opinion  concerning    Caro  to  be  ex. 
the  great  care  which  should  be  exercised  in  regard  to  t 
wicks  used  in  light-house  lamps,  and  stated  that  in  the 
French  service  very  great  precaution  is  adopted  in  procur- 
ing and  inspecting  them. 

After  my  visit  to  the  Depot  des  Phares  I  visited  the  light- 
houses at  the  mouth  of  the  Seine,  and  on  my  return  to  Paris 
I  found  the  following  note  from  M.  Eeynaud: 


190  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

"COMMISSION  DES  PHAK.ES, 

"  Paris,  July  19,  1873. 

"M.  Eeynaud  much  regrets  not  having  been  at  the  Depot 
des  Phares  when  Major  Elliot  did  him  the  honor  to  call. 

"  It1  Major  Elliot  wishes  to  see  M.  Eeynaud  on  business,  he 
will  find  him  at  the  Depot  des  Phares,  Avenue  de  VjEmpereur, 
corner  of  la  place  Trocadero,  to-morrow,  Wednesday,  from 
2  to  4  o'clock.  His  approaching  departure  obliges  M. 
Eeynaud  to  indicate  an  hour  instead  of  asking  Major  Elliot 
to  name  one  that  would  be  convenient  for  him.  He  hopes 
to  be  excused,  and  presents  Major  Elliot  his  best  compli- 
ments. 

"  L.  EEYNAUD." 

On  my  arrival  at  the  depot  at  the  time  appointed,  M.  Eey- 
naud received  me  with  cordiality  and  expressed  his  desire 
to  assist  me  in  the  object  of  my  mission  by  any  means  in 
his  power. 

Question  of  ii-     Our  conversation  turned  mostly  upon  the  subjects  of  illu- 
iampsantl         dminants  and  burners  for  light-houses,  they  being  the  ques- 
tions now  of  greatest  interest  to  the  light-house  engineers 
of  Europe,  and  I  found  the  French  fully  as  much  interested 
in  this  subject  as  are  the  English. 

order  of  French  ^'  Rvynaud  stated  that  the  Commission  des  Phares  had  re- 
fubstitSt^miner0  cew%  given  an  order  for  the  substitution  of  mineral  for  colza 
ai  for  colza  oil.  On  {n  au  Of  fjie  French  light-houses,  and  their  lamps  were  being 
changed  for  this  purpose  as  fast  as  possible  ;  that  no  difficulty 
whatever  is  found  in  its  use  ;  that  it  is  perfectly  safe  when  in- 
spected, and  received  after  proper  tests  ;  and  that,  while  the 
consumption  by  the  larger  orders  of  lamps  is  about  the  same,  it 
is,  for  the  smaller  orders,  very  much  less  than  the  consumption  of 
colza,*  while  its  cost  per  gallon  is  about  one  half,  and  the  light 
produced  is  superior  and  the  lamp  more  easily  managed,  a  change 
of  wicks  being  required  only  at  long  intervals,  the  full  power 
without  trimming  being  kept  up  from  sunset  to  sunrise. 
Burner  in  use.  The  burner,  or  bee  as  it  is  called  by  the  French,  now  in 
use,  is  denominated  the  bee  de  V Administration.  It  combines 
the  peculiarities  of  the  Doty  and  tbe'Fresnel  burners,  with 
modifications  made  by  the  Commission,  especially  in  regard  to 
the  overflow.  By  an  ingeniously  devised  screw  the  overflow 
is  regulated  to  suit  the  temperatures  of  different  climates, 
which  is  highly  important. 

*  It  will  be  found  by  reference  to  my  account  of  the  improvements  in 
lamp-burners  made  by  Mr.  Douglass,  engineer  of  Trinity  House,  that  in 
consumption  and  illuminating  power,  colza  has  been  brought  to  an  equality 
with  mineral  oil. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  191 

In  regard  to  the  claims  of  Captain  Doty,  which  have    Question     of 

,        .  ,  ,.      ,  claim  of  Captain 

caused  much  controversy  in  England,  M.  Keyuaud  said  that  Doty  as  inventor. 

Captain  Doty  presented  his  burner  without  conditions  to  the 

French  government,  and  it  had  paid  him  a  certain  amount, 

(not  stated  to  me,)  not  as  payment  for  an  invention,  but 

rather  as  a  reward  for  calling  attention  to  the  economy  and 

other  advantages  of  mineral  oil  for  use  in  light-houses,  and 

pressing  its  claims  for  adoption  over  the  vegetable  and 

animal  oils.    I  afterward  ascertained  that  the  French  gov-    indemnity  paid 

Captain  Doty  by 


ernment  paid  to  Captain  Doty  an  indemnity  of  10,000  francs,  noh  gov" 

($2.000,)  and  purchased  his  burners  at  44  francs  ($8.80)  each, 
being  an  excess  of  19  francs  ($3.80)  over  the  cost  of  the 
burners  formerly  used. 

In  this  connection  the  following  recent  letter  from  the 
Minister  of  Public  Works  of  France  to  the  British  Embassa- 
dor  in  Paris  will  be  found  of  interest  : 

"  VERSAILLES,  August  12,  1873. 

"  M.  L'AMBASSADEUR  : 

"  In  acknowledging  the  reception  on  the  16th  of  June 
last  of  various  documents  relative  to  the  illumination  of 
light-houses  with  mineral-oil,  your  Excellency  has  done  me 
the  honor  to  express  to  me  in  the  name  of  the  Board  of  Trade 
the  desire  of  learning  whether,  since  the  publication  of  the 
note  of  M.  Keynaud,  Director  of  the  Light-house  Service, 
he  had  not  arrived  at  some  new  facts  in  support  of  the  obser- 
vations it  contained  on  the  respective  merits  of,  the  Doty 
and  Fresuel  lamps. 

"  Your  Excellency  adds  that  the  Board  of  Trade  would 
equally  appreciate  the  reception  from  M.  Eeynaud  of  the 
fullest  information  relative  to  the  merits  and  price  of  the 
Fresnel  lamp  manufactured  by  M.  Henry  Lepaute. 

ki  The  Minister  of  Public  Works  calls  to  mind  that  the 
note  of  the  Director  of  the  Light-house  Service  indicates  that 
two  kinds  of  burners  were  in  use,  giving  the  same  results, 
viz,  the  Doty  burner  and  the  modified  Fresnel  burner.  Now, 
it  appears  from  recent  information  furnished  by  M.  Eeynaud 
that,  in  consequence  of  divers  changes  in  details  which  the 
experiments  made  at  the  Depot  des  Phares  had  induced  the 
engineers  to  adopt  in  each  of  the  systems,  it  may  now  be 
considered  that  the  two  kinds  of  burners  differ  but  little 
more  than  in  name.  The  light-house  service  includes 
them  in  the  same  designation  of  mineral-oil  burners. 

u  These  burners  consume  the  same  quantity  of  oil,  have 
the  same  luminous  intensity,  and  offer  the  same  guarantee 
of  regular  action. 


192  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

"  Their  cost  is  the  same  to  the  French  government,  viz  : 
"  Burners  with  5  wicks,  60  iraucs. 
u  Burners  with  4  wicks,  50  francs. 
"  Burners  with  3  wicks,  40  francs. 

"  Burners  with  2  wicks,  32  francs. 

#  *  #  *  *  #  * 

"  Accept,  &c., 

«  BEOGLIE. 
"  His  Excellency  LORD  LYONS,  G.  C.  B." 

scotch  mineral-  The  mineral-oil  used  in  the  French  service  is  the  Scotch, 
which  is  found  to  be  safe  and  quite  uniform  in  character; 
and  so  anxious  have  the  Scotch  manufacturers  been  to  sup- 
ply the  French  lights,  and  thus  gain  a  reputation  for  their 
oil,  that  they  not  only  furnish  a  better  article  but  at  cheaper 
rates  than  the  French  refiners. 

Lens-manufac-  In  regard  to  the  three  lens-makers  of  Paris,  M.  Eeynaud 
stated  that  all  were  good  and  conscientious  firms,  and  the 
Commission  des  Phares  made  no  distinction  between  them 
in  giving  4ts  orders  for  optical  apparatus. 

Designs   fur-     Designs  are  furnished  by  the  Commission,  and  a  scale  of 

nished    by  Com- 

mi ssi on    des  prices  is  established  by  it :  these  established  prices  are  lib- 

Phares.  ...  . 

eral,  the  commission  having  in  view  the  object  of  procuring 
good  material  and  workmanship. 
Competition  in     M.  Eeynaud  thought  that  competition  in  regard  to  prices 

price     likely    to  ,-,.., 

result  iu  inferior  would  induce  a  reduction  in  regard  to  quality,  which  could 
ratus/  c       >a  not  be  thought  of  when  the  desire  is  to  utilize  for  the  bene- 
fit of  mariners  every  ray  of  light  with  the  least  possible 
loss  of  the  power  with  which  it  issues  from  the  flame  of  the 
light-house  lamp. 

As  before  stated,  all  lenses  made  for  the  Commission  are 

thoroughly  tested  at  the  Depot  des  Phares  before  being  sent 

to  the  district  engineers  for  placing  in  the  light-houses,  and 

to  the  interest  felt  by  the  government  of  France  in  lens- 

manufacture,  first  commenced,  after  the  invention  of  Fres- 

nel,  in  the  city  of  Paris,  is  due  the  kind  offer  made  to  me  by 

nMde?o°fest  Jens"  "^'  ^eynandj  to  apply  the  photometric  and  other  tests  to  any 

es    ordered   by  lenses  which  might  thereafter  be  ordered  from  Paris  by  the 

United  States. 

American  Government. 

Lenses  for  eiec-  Eeferring  to  the  electric  lights,  of  which  France  has  four, 
M.  Eeynaud  remarked  that  the  smaller  lenses  are  better 
than  the  larger  ones,  and  that  diagonal  bars  should  be  used 
for  the  panels ;  as  for  the  lantern,  the  glass  can  readily  be 
cast  in  one  piece  and  the  use  of  sash-bars  thusavoided,  which 
is  highly  desirable  for  these  lights. 

f°r     ^u  sPea^n&  of  the  construction  of  lanterns  for  oil-lights, 
he  gave  as  his  opinion  that  vertical  sash-bars  do  not  mate- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  193 

rially  interfere  with  the  beam,  thus  differing  from  the  well- 
known  opinions  and  practice  of  the  English  and  Scotch 
engineers. 

M.  Keynaud  called  my  attention  to  his  Memoire  sur 
V  Eclair  age  des  Cotes  de  France  as  containing  much  informa- 
tion on  the  subject  of  the  administration  of  the  French 
light-house  service  ;  also  to  his  paper  on  the  Application  de 
VHuile  Hinerale  a  VlUclairage  des  Phares,  (1873,)  a  translation 
of  which  will  be  found  below.  1  am  much  indebted  to  M. 
Eeynaud  and  to  M.  Allard  for  the  facilities  afforded  me  for 
gaining  information  while  at  the  Depot  des  Phares,  and  the 
former  was  good  enough  to  say  that  he  would  be  glad  at  all 
times  to  furnish  the  Light-House  Board  of  the  United  States 
with  any  information  concerning  the  improvement  of  French 
lights,  or  on  any  other  points  that  might  be  desired,  and  ex- 
pressed a  hope  that  our  Board  would  keep  the  French  Board 
advised  of  its  progress  in  the  science  of  light-house  illumi- 
nation. 

[Translation.] 

APPLICATION    OF    MINERAL-OIL    TO   LIGHT-HOUSE    ILLUMI- 

NATION. 

BY  M.  LEONCE  REYNAUD, 

Inspector-  General  of  Engineers  (des  Fonts  et  Chausse'es)  and  Director  of  the 
French  Light-house  Service. 

The  question  whether  mineral-oil  can  be  practically  used 
for  light-house  illumination  has  been  studied  for  several 
years  and  finally  answered.    A  Ministerial  decision  of  March 
29,  1873,  made  in  conformity  to  a  recommendation  of  the    order   of  the 
Light-  House  Commission,  ordered  that  the  new  combustible  menT  forguse'oi 


be  substituted  for  colza-oil  in  all  the  lights  of  the  coast,  mineral-oi 


except  the  floating-lights,  for  which  experiments  have  not 
yet  shown  it  satisfactory. 

The  object  of  this  article  is  to  show  how  this  measure 
came  to  be  adopted,  and  to  examine  its  merits,  both  in  re- 
spect to  maritime  interests  and  to  economy. 

In  1856  the  engineers  of  the  central  light-house  service    Experiments 
commenced  a  series  of  experiments  with  oil  extracted  from  witb  80hist-°il8- 
bituminous  schists  of  the  Department  of  Allier,  and  soon 
saw  that  the  Maris  lamp  (so  called  after  the  name  of  its    superiority  of 
constructor)  was  better  than  all  others  then  in  use,  theto?s£srt8oiiam 
flame  being  more  intense  and  requiring  less  attention.    This 
lamp,  still  in  use,  has  a  single  cylindrical  wick.    A  metallic 
disk  throws  the  interior  air  current  on  the  flame  ;  below  the 
burner  is  a  rather  large  cistern,  into  which  the  wick  de- 
S.  EX.  54  -  13. 


194  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

scends,  and  the  oil  rises  by  capillary  attraction,  without  the 
aid  of  any  mechanism  whatever.  The  flame  is  more  ex- 
tended than  in  colza-oil  lamps,  being  broader  and  shorter, 
but  with  lens-apparatus  this  is  an  advantage  rather  than 
otherwise,  especially  when  the  catadioptric  rings  have  been 
Eeflector-appa-  calculated  to  correspond.  In  reflector-apparatus,  however, 

rat  us  require  con'  x 

stuut-ievei  lamp,  this  lamp  cannot  be  used,  on  account  of  the  position  and 

size  of  the  cistern,  this  apparatus  admitting  only  the  use 

of  constant-level  lamps,  the  level  a  few  centimeters  below 

the  crown  of  the  burner. 

intensity  of     The  intensity  of  small  lens-apparatus  lighted  by  a  Maris 

tagminerS-oiL  "laflIP  burning  mineral-oil,  is  nearly  double  that  obtained 
with  an  equal  consumption  of  colza-oil,  arid  as  the  former 
is  much  cheaper,  it  was  evidently  best  to  continue  the  trials, 
and,  if  prudent,  to  adopt  it. 

Mineral-oil  first  Iu  1857  and  1858  mineral-oil  was  used  for  a  few  harbor- 
lights.  Mariners  were  well  satisfied  with  them,  and  the 
keepers  themselves,  who  at  first  had  shown  some  hesita- 
tion, came  to  acknowledge  that  the  flames  kept  better  than 
formerly,  without  requiring  as  much  attention.  But  some 
Accidents.'  accidents  occurred,  which,  although  not  of  a  nature  to 
cause  an  abandonment  of  the  new  system,  showed  that 
great  caution  was  necessary ;  an  ill-regulated  flame  smoked 
so  badly  that  the  light  was  extinguished  shortly  after  light- 
ing;  a  cistern  exploded;  at  another  place  the  chimney  and 
the  upper  rings  of  the  apparatus  were  broken. 
continuation  of  Experiments  were  then  continued  at  the  light-house 

experiments.  depot,  both  with  the  different  mineral-oils,  and  in  regard  to 
the  measures  to  be  taken  for  the  desired  security.  At  the 
same  time  the  use  was  extended  on  our  coasts,  and  soon 
every  serious  reason  for  hesitation  disappeared,  at  least  as 
far  as  regarded  its  use  in  single-wick  lamps.  At  the  end  of 
1864  the  new  combustible  was  used  in  forty-one  harbor- 
lights,  and  the  following  year  it  was  ordered  to  be  exclu- 
sively used  in  all  fourth-order  apparatus,  i.  e.,  in  all  single- 
wick  lamps. 

But  the  numerous  attempts  made  by  engineers  and  man- 
ufacturers to  use  mineral-oil  in  lamps  of  the  superior  orders, 
(which  have,  as  is  well  known,  several  concentric  wicks) 
did  not  succeed ;  the  combustion  was  incomplete,  brilliancy 
feeble,  smoke  sometimes  abundant. 
Doty  lamp-  While  we  were  still  experimenting,  Captain  Doty,  an 

burner.  American,  succeeded  in  solving  the  problem  which,  until 

then,  had  baffled  all.  In  1868  Mr.  Doty  brought  forward  a 
lamp  for  burning  mineral-oil,  having  four  concentric  wicks, 
which  was  tested  according  to  the  method  adopted  at  the 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  195 

light-house  depot.  This  lamp,  unlike  the  one  with  a  single 
wick,  did  not  give  greater  intensity  than  that  obtained 
from  lamps  of  the  same  order  consuming  colza-oil;  but  the 
consumption  was  less,  and  the  combustible  being  cheaper, 
a  considerable  saving  to  the  treasury  would  result  from  its 
use.  Besides,  navigation  would  gain  somewhat,  for  al- 
though the  intensity  immediately  after  lighting  was  the 
same  as  that  of  the  old  lamps,  it  was  kept  up  longer,  and 
did  not  decrease  as  much  toward  morning. 

On  recommendation  of  the  Light-house  Commission,  it 
was  decided  that  a  practical  trial  of  this  system  should  be 
made.  The  mouth  of  the  Canche  is  marked  by  two  first-  ^fi^g  "jf^g- 
order  fixed  lights,  placed  on  a  line  parallel  with  the  shore,  Jo  uses  at  m<mth 
about  820  feet  apart ;  one  of  them  was  lighted  with  mineral- 
oil  from  December  12,  1868,  to  January  26,  1869.  The  sub- 
sequent investigation  fully  corroborated  the  conclusions 
derived  from  the  Paris  experiments.  The  two  lights  were 
apparently  of  the  same  intensity  when  first  lighted;  the 
consumption  of  the  mineral-oil  was  about  17  per  cent,  less 
than  that  of  colza ;  its  flame  was  easier  to  manage  and  kept 
better.  At  first  the  odor  was  somewhat  offensive  to  the 
keepers,  but  they  became  accustomed  to  it  and  did  not  feel 
the  least  inconvenience. 

Meanwhile  Captain  Doty  had  some  two  and  three  wick  increase  of  iu- 
lamps  made,  which,  without  increasing  the  luminous  inten-  teh  r^e 
sity  in  as  great  a  proportion  as  the  single- wick  lamps, lamp8' 
showed  themselves  superior  in  this  respect  to  similar  ones 
burning  colza-oil.  These  results  were  encouraging,  but  the 
fear  of  explosion  still  remained,  and  caused  all  the  more 
uneasiness  as  a  report  kindly  furnished  by  the  Chairman  of 
the  Light-house  Board  of  the  United  States  of  America,  who 
had  been  consulted  on  this  subject,  stated  that  in  that 
country,  where  mineral-oil  is  abundant,  it  had  not  been 
thought  advisable  to  use  it  in  light-houses  on  account  of  its 
inflammability,  the  dangers  of  which  were  but  too  well  at- 
tested by  numerous  accidents. 

But  a  new  kind  of  mineral-oil,  extracted  from  bog-head*  scotch paraffi 
and  called  Scotch  paraffine,  had  been  successfully  used 
at  the  light-house  depot,  was  found  to  be  much  less 
inflammable  than  the  schist-oil  used  till  then,  and  was 
used  in  one  of  the  light-houses  of  the  Canche.  Conse- 
quently the  engineers  saw  that,  before  proceeding  farther, 
it  would  be  necessary  to  test  the  comparative  merits  of  the 
different  oils  in  market,  excluding,  however,  American  pe- 
troleum, the  composition  and  properties  of  which  are  too 
*  Local  name  for  eannel  coal. — G.  H.  E. 


196 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Table  of  com- 
parative values 
of  oils. 


variable.  They  ascertained  the  qualities  as  to  luminous  in- 
tensity and  consumption,  and  Chief-Engineer  Maugon  had 
the  kindness  to  undertake  to  determine,  with  his  usual  ac- 
curacy, the  flashing-points  and  other  properties  useful  to 
know. 
The  following  table  gives  the  figures  obtained : 

Table  of  comparative  values  of  oils. 


2| 

'o 

o 

Iti 

•53,3 

&&*. 

^ 

ci 

§|^ 

'S3  o  q 
p  o  a 

|| 

j 

% 

«§» 

Designation  of  oils. 

.2 

||a 

.2 

| 

ii 

P 

1 

§£•§ 

'fL-^ 

gj 

$ 

2  §* 

8 

g-c'o 

S'c 

q 

fc£ 

u 

'«  M 

o 

0 

III 

§ 

1 

p 

1 

« 

^ 

o 

w 

M 

£ 

6^ 

Carcel 

Amt.  in 

Fahr. 

Fahr. 

units. 

grams. 

o 

o 

Achaume  at  Autun 

1 

1.56 

25.7 

77.0 

284.0 

0.  827 

0.  084 

J.  Barse,  Mineral  Illumination  Com- 

pany of  Allier,  at  Buxiere  la  Grue  .  . 
Graillot  Brothers,  at  Autun  .  ,  

2 
3 

1.82 
1.63 

21.9 
24.6 

78.8 
84.2 

287.6 
300.2 

0.818 
0.  819 

0.087 
0.087 

Rondeleux,  mines  of  Condamine,  at 

Buxiere  la  Grue  

4 

1.59 

25.2 

84.2 

305.6 

0.833 

0.093 

Hubinet  of  Soubise,  at  Autun  

5 

1.47 

27.2 

98.6 

312.8 

0.830 

0.099 

E.  Goutier  et  Cie,  at  Autun 

6 

1.78 

22.4 

105.  8 

320.  0 

0.825 

0.080 

Civil  Mining  Company  of  L'Autunois  . 
Anonymous  Company  of  the  Oils  of 
Colombes  ..   . 

7 
8 

1.55 
1.60 

25.8 
25.1 

107.6 
114.8 

327.2 
334.  4 

0.831 
0.834 

0.098 
0.090 

Roche  et  Cie,  of  Igonay,  Saone  et  Loire 
Young's  Paraffine  Light  and  Mineral 

9 

1.45 

27.6 

120.2 

345.  2 

0.834 

0,  095 

Oil  Company,  Scotland  

10 

2.18 

18.3 

161.6 

401.0 

0.833 

0.094 

Superiority  of 
Scotch  parafflne. 


*It  will  be  remembered  that  the  unit  of  light  adopted  by  the  Light-house  Commis 
sion  is  the  Carcel  burner,  Om.020  (0.79  inch)  in  diameter,  consuming  40  grams  of 
colza-oil  per  hour. 

The  superiority  of  the  Scotch  oil  was  thus  very  evident 
in  essential  respects,  as  it  proved  to  be  at  the  same  time 
less  inflammable  and  of  greater  illuminating  power  than  the 
others,  and  lessened,  if  it  did  not  completely  obviate,  the 
chances  of  accident.  Still  the  Light-house  Commission, 
wishing  to  be  as  prudent  as  the  gravity  of  the  interests  con- 
fided to  its  care  required,  though  not  more  disposed  than 
in  the  past  to  repel  imprpvements,  confined  itself  to  propos- 
ing at  its  session  of  June  26,  1869,  to  apply  the  new  com- 
bustible to  two- wick  lamps  of  third-order  lights,  and  also  to 
such  three-wick  lamps  as  might  be  used  where  the  colora- 
tion of  the  light  required  a  greater  intensity  of  the  luminous 
focus,  or  where  it  might  be  thought  best  to  increase  the 
diameter  of  the  burner,  in  order  to  obtain  greater  divergence. 
It  was  recommended,  moreover,  to  proceed  to  new  studies 
of  instruments  and  receptacles  having  especially  in  view 
the  prevention  of  accidents. 

The  contract  for  furnishing  mineral-oil  of  French  origin, 
made  with  the  firm  of  Jules  Barse,  expired  at  the  end  of 
the  year.  It  was  not  renewed,  and  another  was  made,  to 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


197 


Contract 
Scotch  oil. 


fort 


run  for  three  years  from  January  17  1870,  with  the  company 
established  in  Scotland  under  the  name  of  "  Young's  Paraf- 
fine  Light  and  Mineral-Oil  Company."  It  was  stipulated  in 
the  conditions  that  the  specific  gravity  should  be  between 
0.81  and  0.82  at  59°  Fahrenheit,  and  that  no  inflammable 
vapors  should  be  produced  at  a  temperature  below  140° 
Fahrenheit.  This  is  much  lower  than  the  161.6°  Fahrenheit 
found  by  M.  Mangon;  it  was  adopted  so  as  not  to  create 
too  many  difficulties  for  the  engineers  as  well  as  for  the  com- 
pany, after  numerous  trials  had  shown  that  it  might  be  con- 
sidered sufficiently  low  as  a  limit  and  still  sufficiently  high 
to  give  entire  security.  The  price  of  the  oil  had  been  fixed 
at  0.85  francs  per  kilogram,  [about  50  cents  per  wine-gal- 
lon,] delivered  at  the  light-houses,  and  is  the  same  in  the 
new  contract  made  with  the  same  company,  to  date  from 
the  1st  of  January  lasfc,  [1873,]  all  customs  duties  aflfecting 
the  product  to  be  refunded.  The  memoir  on  the  illumina- 
tion and  buoyage  of  the  coasts  of  France,  published  in  1864, 
states  that  colza-oil,  the  cost  of  which  varies  with  the  mar- 
ket, averages  1.51  francs  per  kilogram,  [about  $1  per 
wine-gallon,]  *  delivered  at  the  light-houses.  It  will  be  seen 
that  the  difference  is  great.  • 

Mineral-oil  is  used  in  all  third  and  fourth  order  lights  Minerai-oii  m 
established  since  the  commencement  of  1870,  in  conformity  Souses. 
with  a  recommendation  of  the  Light-house  Commission,  made 
mandatory  by  a  Ministerial  decision.  We  now  use  it  in  one 
hundred  and  sixteen  light-houses,  six  of  which  are  of  the 
third  order.  There  is  even  one  light  of  the  second  order, 
viz,  that  of  Pilier,  which,  as  a  considerable  part  of  the  arc 
of  illumination  had  to  be  colored  red,  has  been  furnished 
with  a  five- wick  lamp,  as  will  be  explained  hereafter.  Thirty- 
nine  third-order  lights  yet  burn  colza-oil,  and  considering 
that  the  advantages  of  change  are  well  established,  it  may 
be  thought  that  its  progress  has  been  exceedingly  slow. 
But  besides  the  trouble  caused  by  the  misfortunes  of  the 
country,  there  were  several  reasons  for  caution  on  the  part 
of  the  engineers  of  the  central  service. 

Sensible  of  their  responsibility,  they  asked  themselves    Questions    of 

,  expense.  &c.,  re- 

whether  the  new  combustible  would  not  show  in  actual  suiting   from  a 

,  ,     ,        . ,       -.-^  change    of     illn- 

practice  some  disadvantages  not  brought  out  by  the  Pans  mmants. 
experiments,  and  whether  it  would  retain  the  valuable  quali- 
ties which  caused  it  to  be  preferred  to  all  other  oils,  and  so 
recommended  by  the  Commission.  Besides,  it  was  admitted 
by  all,  even  by  the  contractors  themselves,  that  special  re- 
ceptacles were  necessary  for  mineral-oil,  and  hence  there 


Taking  the  specific  gravity  of  colza  as  0.914. 


198 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


suits. 


would  result  expenditures,  which  the  smallness  of  our  ap- 
propriations would  require  to  be  several  times  recommenced. 

NO  accidents.  None  of  these  reasons  for  delay  now  exist.  During  the 
three  years  that  the  Scotch  paraffine  has  been  used  in  the 
light-house  service,  not  an  accident  has  occurred,  not  a  disad- 

satisfactory  re-  vantage  has  been  found.  Mariners,  engineers  on  the  coasts, 
even  the  keepers,  all  show  themselves  entirely  satisfied. 
The  article  produced  by  the  Scotch  company  has  lost  none 
of  its  qualities.  Finally,  experiments  made  at  the  light- 
house depot  for  the  last  two  years  have  shown  that  the 

coiza-oii  tanks  large  colza-oil  tanks  lined  with  tin,  now  used  in  our  light- 
stutabie  for  par-  houseg?  are  equally  suitable  for  holding  mineral-oil.  It  has 
even  been  proved  that  this  oil  can  be  preserved  for  three 
years,  at  least,  in  well-secured  tin  cans,  without  losing  any 
of  its  qualities.  In  zinc,  however,  it  does  not  do  as  well, 
although  it  does  not  become  unsuitable  for  use. 

A  fact  already  mentioned,  has  again  been  placed  beyond 
question,  and  it  is  of  capital  importance :  for  an  equal  in- 
tensity less  mineral  than  colza  oil  is  consumed,  whatever 
may  be  the  number  of  wicks,  as  will  be  seen  by  the  follow- 
ing table,  of  which  the  figures  may  be  considered  as  the 
maxima  of  both  kinds  of  oil : 


Economy. 


No.  of  wicks. 

Colza-oil. 

Mineral-oil. 

Consumption  per  hour. 

Luminous 
intensity. 

Consumption  per  hour. 

Luminous 
intensity. 

1  

In  grams. 
CO 
175 
500 
760 

In  fluid  oz.* 
2.25 
6.55 
18.73 
28.46 

Carcel  units. 
1.6 
5.0 
15.0 
23.0 

In  grams. 
55 
160 
360 
630 

In  fluid  oz* 
2.29 
6.65 
14.97 
26.20 

Carcel  units. 
2.2 
6.4 
14.0 
23.0 

2 

3          .     . 

4  

*  128  to  the  wine-gallon. 

In  looking  over  this  table  it  may  appear  anomalous  that 
while  the  mineral-oil  produces  a  greater  intensity  than  colza 
in  one  and  two  wick  lamps,  and  the  same  in  four-wick 
lamps,  it  produces  less  in  three-wick  lamps,  (fourteen  in- 
!  stead  of  fifteen  burners.)  This  results  from  the  fact  that, 
for  the  sake  of  uniformity,  it  was  thought  best  to  adopt  in 
the  new  lamps,  the  same  diameters  for  all  the  wicks  of  the 
same  rank,  which  had  not  been  done  in  the  successive 
establishment  of  the  different  types  of  colza-oil  lamps. 
Wick  No.  3,  which  fixes  the  diameter  of  three-wick  lamps, 
is  2.71  inches  in  diameter  in  colza-oil  burners,  and  only 
2.55  inches  in  those  for  mineral-oil.  It  may  also  be  re- 
marked that  the  saving  of  oil  is  comparatively  greater  in 
Question  oflamps  of  this  order,  and  by  somewhat  enlarging  the  wicks 
bfeS  S  wicks™11"  both  consumption  and  luminous  intensity  would  be  increased. 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  199 

These  facts  established,  it  seemed  that  the  proper  mo- 
ment had  come  to  order  the  substitution  of  mineral  for  colza 
oil  in  all  the  light-houses:  and  at  the  same  time  the  ques- 
tion occurred  whether  it  would  be  advisable  to  allow  (as 
had  been  done  before  in  the  case  of  third-order  lights) 
lamps  with  more  than  the  regulation  number  of  wicks  to 
be  used  in  first  and  second  order  light-houses,  where  greater 
intensity  appeared  desirable. 

This  measure,  as  before  stated,  had  already  been  adopted 
in  the  exceptional  case  of  the  Pilier  light.  As  the  Light-  at°n  of 
house  Commission  proposed  to  color  this  light  red,  in  a  cer- 
tain angular  space,  to  warn  mariners  from  the  shoal  of  Les 
Boeufs,  and  did  not  wish  to  lessen  its  range,  it  was  neces- 
sary to  increase  the  intensity  of  the  focus;  so  it  was  thought 
best  to  use  mineral-oil  with  five  instead  of  three  concentric 
wicks.  This  experiment  was  crowned  with  entire  success. 

The  engineers  of  the  central  service  hesitated  much 
before  deciding  in  favor  of  a  change,  and  their  hesitation 
increased  when  they  perceived  the  consequences  of  innova- 
tion. While  inclined  to  propose  an  increase  in  the  number 
of  wicks,  they  were  prevented  by  a  consideration  most 
powerful  with  them,  the  profound  respect  which  they  enter- 
tain for  the  memory  of  their  illustrious  predecessor.  Augus- 
tin  Fresnel,  after  many  experiments  and  mature  consider- 
ation, established  the  relations,  till  now  observed  not  only 
in  France,  but  by  all  maritime  powers,  between  the  diame- 
ters of  the  burners  and  the  dimensions  of  the  lens-appa- 
ratus, and  it  will  be  easily  understood  that  imperious 
necessity  alone  would  excuse  any  alteration.  It  was,  how- 
ever, soon  remembered  that  there  was  at  the  light-house 
depot  a  few  years  ago  a  gas-burner  originating  with  An- 
gustin  Fresnel,  which  had  five  concentric  rings  of  small nel- 
apertures.  Unfortunately  this  burner  is  lost.  The  brother 
of  the  illustrious  inventor  borrowed  it  to  make  an  engrav- 
ing; it  was  destroyed  by  fire,  and  the  engraving  (annexed 
to  FresnePs  complete  works)  does  not  give  the  dimensions. 
Still  the  scale  on  which  it  is  shown  is  sufficiently  large 
(0.25)  to  justify  some  confidence  in  measurements  taken  by 
dividers,  and  thus  it  was  found  that  the  diameter  of  the 
exterior  ring  must  have  been  about  4.72  inches,  while  the 
same  diameter  (taken  in  the  middle  of  the  thickness  of  the 
wick)  is  but  3.34  inches  in  first-order  colza-oil  lamps  and 
4.13  inches  in  5  wick  mineral -oil  lamps.  It  is  to  be  ob- 
served, moreover,  that  the  text  (vol.  3,  page  514)  clearly  nosircd  in- 

i  fl    .,        .  ..  crease    of    dura- 

shows  that  the  aim  of  the  invention  was  to  increase  the  tion  of  flashes  m 
duration  of  flashes  in  eclipse-lights,  and  that  this  result  eclipse-lishta 


200  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

could  be  obtained,  as  regards  the  burner,  only  by  an  increase 
in  diameter.  Thus  we  have  the  proof  that  this  was  one  of 
the  inventor's  efforts  to  prolong  the  duration  of  the  lumi- 
nous apparitions  in  eclipse-lights  5  the  only  objection  to  the 
new  lens-apparatus  being  that  it  was  inferior  in  this  respect 
to  the  old  reflectors $  and  it  is  known  that  in  the  two  first- 
Fresuei  lamp,  order  eclipse-lights  constructed  during  the  life- time  of  Fres- 
nel  (Cordouan  and  Planier)  the  luminous  rays  passing 
above  the  drum  are  used  entirely  to  prolong  the  flashes 
produced  by  the  principal  lenses  5  the  inventor  thus  sacri- 
ficing intensity  to  duration. 

It  is  easily  understood  why  he  did  not  exceed  four  wicks 
and  the  resulting  diameter  when  the  combustible  was  colza- 
oil.  A  considerable  increase  of  expense  would  have  been 
the  result,  and  thus  an  arm  might  have  been  furnished. to 
the  opponents  of  the  new  invention.  There  was  also  danger 
of  meeting  with  practical  difficulties,  since  there  was  no 
certainty  that  such  vigilance  as  a  four-wick  lamp  requires 
could  be  obtained  from  light-keepers ;  and,  indeed,  it  was 
some  years  before  we  could  succeed  in  this  respect.  ^ 

Thus  it  may  be  inferred  that  Augustin  Fresnel  considered 
the  four-wick  burner  the  highest  limit  which  could  be  ob- 
tained with  colza-oil,  and  that  he  sought  for  a  new  com- 
bustible which  might  allow  him  to  proceed  further.  It  is, 
therefore,  only  carrying  out  his  ideas,  to  use  mineral-oil  in 
order  to  increase  to  a  certain  extent  the  dimensions  of 
burners.  It  is  also  to  be  remarked  that  the  height  of  the 
flame  is  riot  increased,  so  that  multiplying  the  wicks  mostly 
affects  the  horizontal  divergence,  which  is  all  used  for  sea- 
illumination. 

A  final  question  was  considered,  whether  instead  of  con- 
fining the  advantages  of  the  measure  to  a  certain  number 
of  lights,  it  would  not  be  better,  although  more  expensive, 
to  give  each  apparatus  of  the  same  order  the  same  number 
of  wicks.  As  this  would  be  a  more  regular  system,  and 
give  more  security  to  mariners,  the  Light-house  Commission 
Proposal  to  reg-  did  not  hesitate  to  answer  it  in  the  affirmative.  They  pro- 

ulate  the  number  ITT.          f  •> 

of  wicks  and  or- posed  to  make  five  orders  of  lights,  establishing  for  each  a 

constant  proportion,  more  decided,  however,  than  before, 

between  the  diameter  of  the  burner  and  that  of  the  lens- 

Compar  ati  ve  apparatus.     The  following  comparative  table  of  the  old  and 

table  of  old  and  . ,  n   .,        ,     ,  ,      , , 

new  systems,      new  systems  shows  the  advantage  of  the  latter,  both  to 
mariners  and  the  public  treasury  : 


EUROPEAN   LIGHT- HOUSE    SYSTEMS. 


201 


202 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


Results  pro-  The  preceding  table,  which  clearly  shows  that  the  new 
iightJin  se"  system  notably  increases  the  intensity  of  fixed  lights,  shows 
nothing  as  to  eclipse-lights,  for  the  reason  that  with  the 
latter  the  advantages  gained  are  divided,  between  increase 
of  intensity  and  increase  of  duration  of  the  luminous  appa- 
ritions, and  the  figures  showing  the  effect  on  each  of  these 
two  phenomena  vary  greatly  for  each  order  of  lights,  ac- 
cording to  the  number  of  divisions  of  the  lenticular  drum, 
the  rapidity  of  rotation,  and  the  arrangements  for  prolong- 
•  ing  the  flashes.  Therefore,  without  unnecessary  details,  we 
shall  only  give  the  proportional  values,  constant  in  each 
order,  of  the  increase  of  intensity  and  of  duration  which  the 
new  lamps  give  to  the  flashes  of  eclipse-lights. 

Table  of  increase  in  eclipse-lights. 


Order  of  light. 

Proportional  increase. 

Intensity. 

Duration 
of  flashes. 

First 

Per  cent. 

7 
26 
76 
35 

Per  cent. 
22 
22 

59 

58 

Second. 

Third       ... 

Fourth 

Fifth  *  

*  There  are  no  fifth-order  eclipse-lights  on  the  coasts  of  France. 

Besides,  whether  the  light  is  fixed  or  eclipse,  the  quantity 

of  light  emanating  from  the  apparatus  is  constant  for  each 

order,  and  it  may  be  concluded  from  the  above  figures  that, 

as  our  sea-coast  lights  now  are,  the  total  intensity  of  the 

increase  of  in-  luminous  beams  sent  to  the  horizon  will  be  increased  nearly 

tensity  by  use  of 

mineral-oil.  45  per  cent.  This,  however,  does  not  take  into  account  the 
very  considerable  advantage  resulting  from  the  fact  that 
flames  fed  by  mineral-oil  preserve  their  brilliancy  longer 
than  the  others.  The  percentage  would  be  much  higher  if 
the  comparison,  instead  of  being  made  when  the  lights  are 
in  their  first  condition,  were  made  after  they  have  been 
burning  for  a  few  hours.  The  annual  saving  in  oil  will 
amount  to  106,676.80  francs,  ($20,268.59,)  about  32  per  cent. 
Recapitulation  Thus  the  advantages  of  the  change  are  that  45  per  cent. 

tneatcnangeges  °  more  light  is  sent  to  the  horizon,  and  32  per  cent,  'is  saved  in 
the  expense  of  oil. 

There  is,  however,  one  objection  to  the  new  mode  of  illu- 
mination: it  depends  on  the  qualities  of  a  foreign  article. 
This  may  be  adulterated,  its  price  increased  more  or  less 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  203 

when  its  merits,  better  known,  cause  a  greater  demand,  or 
our  supplies  might  be  cut  off  in  case  of  a  maritime  war,  a 
sad  calamity  which  we  must  at  the  present  day  certainly 
take  into  account.  It  is  to  be  observed,  however,  that  the 
formation  of  bog-head  is  very  active,  and  aside  from  their 
own  integrity  the  Scotch  company  will  be  more  interested 
to  maintain  the  reputation  of  their  article  the  more  their 
customers  increase;  the  French  manufacturers  also  will 
probably  be  induced  by  foreign  competition,  and  perhaps 
by  governmental  regulations,  (which  would  certainly  be 
justifiable,)  to  improve  the  article  they  manufacture,  if  not 
as  to  luminous  intensity,  at  least  as  to  safety  ;  wars,  more- 
over, have  ceased  to  be  of  long  duration  ;  finally,  the  burners 
of  our  mechanical  lamps  are  so  arranged  that  in  order  to  go 
back  to  colza,  we  have  only  to  close  the  tube  regulating  the 
level  of  mineral-oil.  All  our  mechanical  lamps  will  be  re- 
tained and  kept  in  use ;  the  burners  alone  will  be  altered. 
There  are  at  present  two  kinds  of  burners  in  use,  both  of  Kimls  of  burn 

ers  in  use 

which  give  the  same  results;  the  Doty  burner,  manufac- 
tured in  Paris  by  Messrs.  Barbier  &  Fenestre,  and  another 
made  by  Messrs.  Henry-Lepaute,  called  the  modified  Fres- 
uel  burner. 

To  complete  the  change  now  commenced  of  colza-oil  lamps 
to  mineral-oil  lamps,  and  to  purchase  the  various  receptacles 
and  implements  needed,  will  not  require  more  than  50,000 
francs  ($9,500)  more.  This  amount  will  be  saved  in  less 
than  a  year  by  the  new  system. 

THE  LENS-MAKERS  OF  PARIS. 

During  my  limited  sojourn  at  Paris  I  visited  the  manufac- 
tories  of  MM.  Henry-Lepaute,  MM.  Sautter,  Leinonnier  & 
Co.,  and  MM.  Barbier  &  Fenestre.  These  three  firms  were, 
until  the  establishment  of  the  works  of  Chance,  Brothers  & 
Co.,  in  England,  the  exclusive  manufacturers  of  dioptric 
apparatus,  and  supplied  all  countries.  They  all  have  exten- 
sive establishments,  and  are  contractors,  not  only  for  lenses, 
but  for  light-houses,  (particularly  small  ones  of  iron,)  for  dif- 
ferent European  countries. 

The  method  of  grinding  and  polishing  the  prisms  and 
lenses  is  almost  identical  at  the  different  establishments, 
all  of  which  keep  on  hand  a  large  stock  of  prisms,  adapted 
to  different  sizes  of  apparatus,  so  that  orders  can  be  filled 
by  them  with  but  little  delay.  Lenses,  lamps,  and  lanterns 
were  in  different  stages  of  manufacture  under  orders  from 
different  countries. 


204  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Establishment  At  M.  Lepaute's,  in  the  faubourg  Saint  Germain,  I  was 
plute.  Henry"Le'  shown  among  others  a  beautiful  third-order  lens,  a  dupli- 
cate of  which  I  afterward  saw  at  the  Industrial  Exhibition 
at  Vienna. 

Lens  shown.  It  was  for  a  "  fixed  light  varied  by  flashes, "  180°  being 
provided  with  fixed-light  apparatus,  and  the  other  half 
divided  into  eight  flash-pauels ;  the  characteristic  of  the 

Characteristics,  light  would  therefore  be,  that  between  comparatively  long 
periods  of  fixed  light,  there  would  be  observed  eight  short 
consecutive  flashes;  quite  a  new  characteristic  and  a  most 
distinctive  one  for  a  light  to  be  placed  within  short  dis- 
tances from  other  varieties  of  lights. 

Swedish  light-  M.  Lepaute  showed  me  his  designs  of  a  tower  and  diop- 
tric apparatus  for  a  light-ship  the  construction  of  which  he 
was  about  to  commence  for  Sweden.  This  design  will  be 
readily  understood  by  an  inspection  of  Plate  XXXI. 

Description  of     I  was  much  interested  in  modifications  of  apparatus  for 

apparatus       for 

floating  lights,  floating  lights,  and  am  indebted  to  him  for  a  paper  on  the 
subject,  from  which  the  following  extracts  are  translated. 
After  describing  the  ordinary  catoptric  fixed  light,  he  says  : 
"  The  arrangement  of  revolving  floating  lights  is  similar  to 
those  of  fixed  floating  lights,  but  the  reflectors  are  36  cen- 
timeters in  diameter,  and  but  eight  in  number,  the  same  as 
the  faces  of  the  lantern.  The  entire  system  of  lamps  and 
reflectors  is  supported  by  a  chariot  on  rollers  which  has  a 
wheel  toothed  on  the  inner  side,  to  which  a  rotary  move- 
ment is  given  by  a  pinion  which  communicates  by  means  of 
a  stem  fixed  by  collars  along  the  mast,  with  the  clock-work 
placed  between  the  decks.  A  special  mechanism  has 
been  added  to  the  floating  light  at  Dunkerque,  so  that  when 
the  sea  is  too  boisterous  it  may  be  hoisted  only  half-way  up 
the  mast  and  yet  be  made  to  revolve. 
Construction  of  "  For  several  years  attempts  have  been  made  to  construct 

floating    dioptric  ,,         .  ,.  .,.,  „  •.-,*,•    -,     i          -, 

lights.  floating  dioptric  lights.    One  method  which  has  been  em- 

ployed, is  to  suspend  on  gimbals  to  an  armature  sliding  along 
the  mast,  three  harbor-lights  (feux  de  port)  lighting  235° 
each  with  its  lantern. 

"  There  has  also  been  used  a  system  of  eight  or  ten  small 
dioptric  apparatus  for  signal-lights,  15  centimeters  in  diam- 
inventionof  M.  eter?  suspended  around  a  mast  in  a  single  lantern.    In  1848 
Henry -Lepaute,  our  father  projected  a  system  of  two  fixed  catadioptric  ap- 
paratus, 60  centimeters  in  diameter,  suspended  on  gimbals 
in  a  single  lantern,  and  each  lighted  by  a  two- wick  constant- 
level  lamp.    The  power  of  this  apparatus  is  very  great,  and 
its  service  very  simple. 

"  In  1869  we  recommenced  our  father's  studies  of  an  ap- 


0 

H 

i 
* 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  205 

paratus  for  a  floating  catadioptric  light,  illuminating  the 
whole  horizon,  and  lighted  by  a    single  two-wick  lamp. 
Our  project  was  appreciated,  and  in  1873  we  were  charged 
with  the  construction  for  Sweden  of  an  apparatus  of  this    Swedish  light- 
kind,  placed  in  the  center  of  an  open  iron  frame-work,  which  8hlp- 
takes  the  place  of  the  mast  of  the  vessel.  (See  Plate  XXXI.) 
"  The  engineers,  both  French  and  foreign,  who  have  ex- 
amined  this  apparatus  in   course  of   construction,   have 
expressed  to  us  their  good  opinion  of  the  result  which  can 
be  obtained  by  this  new  arrangement. 

"  For  revolving  lights  we  have  proposed  to  place  before    Moating     re- 
I  the  reflectors,  annular  lenses  of  15  centimeters  focal  dis- volving  ligbts' 
|  tauce,  which  will  considerably  augment  the  range  of  such 
I  an  apparatus. 

"Plate  XXXII  shows  a  floating  eclipse-light,  which  is  ri  o  a  1 1  u  g 
entirely  catadioptric,  composed  of  two  annular  half-appa- e< 
ratus  suspended  on  gimbals  at  the  two  opposite  extremities 
of  the  same  armature,  and  each  lighted  by  a  two-wick 
burner.  These  two  apparatus  are  placed  in  the  same  lan- 
tern. The  objection  that  the  intervals  between  the  flashes 
are  unequal  on  account  of  the  distance  of  the  two  half-ap- 
paratus is  of  but  little  importance,  as  there  is  not  more 
|  than  a  half-second  difference  during  a  rotation  of  four 
j  minutes,  which,  with  three  lenses  in  each  half-apparatus, 
produces  flashes  of  twelve  seconds7  duration. 

"  We  have  just  finished  a  study  of  a  floating  catadioptric    Floating  Cata- 
light  with  a  single  burner  placed  in  a  single  lantern  and  ar-  dloptn 
ranged  similarly  to  the  floating  catadioptric  fixed  light. 

"  By  making  floating  lights  with  a  single  burner  we  have 
the  advantage  of  being  able  to  make  apparatus  of  sizes  vary- 
ing from  the  sixth  order,  30  centimeters  interior  diameter, 
to  the  three  and  a  half  order,  70  centimeters  interior  diam- 
eter. 

"  The  power  of  these  apparatus  is  much  greater  than  that 
of  those  hitherto  used,  and  the  advantage  of  having  but  one 
lamp  makes  the  service  much  easier." 

M.  Lepaute  has  also  on  exhibition  at  his  manufactory  a    Mineral- on 
lamp  suitable  for  burning  mineral-oil,  which  was  designed lamp  of 
by  M.  Lepaute,  Sr.,  in  1845. 

The  papers  in  support  of  his  claim  to  the  original  inven- 
tion of  a  lamp  suitable  for  burning  mineral-oil  in  light- 
houses, as  well  as  the  reasons  for  such  claim,  are  fully  set 
forth  in  an  interesting  paper  on  the  subject  of  light-house 
burners,  written  at  my  request  by  M.  Henry-Lepaute  fils, 
and  which  he  has  kindly  sent  me  since  my  return  to  Amer- 
ica. A  translation  of  it  will  be  found  on  page  208. 


206  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Lamp-valves.      In  the  construction  of  mechanical  lamps  at  this  establish- 
ment, the  valves  are  made  of  calf-bladder,  and  it  was  stated 
that  for  this  use,  this  material  is  superior  to  any  other. 
E  stabiishment     Sautter,  Lemonnier  &  Co.  have  a  very  extensive  establish- 
monnier&rco.  e  ment  near  the  Champ  de  Mars,  and  their  shops  are  largely 
devoted  to  the  manufacture  of  metal-work  of  light-houses. 
°  f     Toe  ParaPets  Pf  light-houses  and  the  floors  of  the  galleries 


or  "  decks,"  as  we  call  them,  are  in  Europe,  ordinarily  of 
stone.  I  saw,  however,  one  making  for  Eussia,  of  cast  iron, 
which  we  have  found  to  be  the  best  material  for  this  pur- 
pose, in  consequence  of  the  leaks  at  the  joints  of  stone, 
caused  by  contraction  and  expansion  due  to  our  extremes  of 
temperature. 

M.  Sautter,  who  speaks  English  with  fluency,  was  attached 
to  the  Eoyal  Commission  which  reported  on  the  condition 
of  the  light-houses  of  Great  Britain  in  1861.  He  has  had 
laut-  mucn  experience  in  the  specialty  of  testing  of  prisms  and 
lenses,  and  I  was  much  interested  and  instructed  in  the  ac- 
count of  the  means  and  care  which  he  takes  to  insure  that 
every  dioptric  apparatus  supplied  from  his  establishment 
shall  be  of  the  highest  standard  of  efficiency.  It  should  be 
stated  in  this  connection  that  the  other  lens-makers  also 
exercise  great  care  in  this  particular. 

I  observed  at  this  establishment  a  handsome  lantern  for 
an  electric  light,  designed  for  the  Industrial  Exhibition  at 
Vienna,  (represented  by  Fig.  24,)  in  which  the  diagonal 
sash-bars  are  reduced  to  a  minimum  thickness,  viz,  one-half 
inch. 

Besides  this  lantern  there  was  an  iron  tower  for  a  harbor* 
urn-  light,  of  good  design  and  workmanship.  I  was  shown  the 
"  Farquhar  w  burner,  of  which  Sautter,  Lemonnier  &  Co.  are 
the  sole  proprietors,  and  which  they  claim  is  superior  to 
all  others  in  that  it  gives  a  whiter  and  higher  flame,  of 
greater  intensity,  caused  by  the  fact  that  the  tubes  for  the 
supply  of  air  to  the  concentric  flames  are  of  such  capacity 
as  to  produce  equal  currents  to  the  interior  and  exterior,  so 
that  the  draught  is  the  same  to  all  parts.  The  flame  is  of  dif- 
ferent shape,  not  being  pointed  like  those  of  ordinary  lamps. 
o  E|tabiishm^t  At  the  establishment  of  Barbier  &  Fenestre,  I  was  shown 
Fenestre.  a  second-order  lens  ordered  by  us  for  Cape  Elizabeth,  a 

second-order  lens  for  Scotland,  a  third-order  lantern  (of 
iron)  for  Uruguay,  to  cost  11,500  francs,  ($2,300,)  and  fifth- 
order  lanterns  (of  bronze)  for  Venice  and  for  France,  cost- 
ing each  3,200  francs,  ($640.) 

oil-cans.  This  firm  were  also  making  a  large  number  of  oil  cans  or 

butts  for  mineral-oil  destined  for  use  in  the  French  service. 


REVOLVING   CATADIOPTRIC  APPARATUS 

FOR  LIGHT-SHIPS.  PLATEXXXII. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Each  of  these,  cans,  which  are  of  sheet-iron,  contains  seven ty- 
five  liters,  (about  20  gallons,)  and  costs  SOfrancs,  ($6.)  They 
are  hung  in  iron  stands  on  pivots  placed  slightly  below  the 
middle,  and  the  cocks  are  at  the  tops  of  the  cans,  the  advan- 
tage claimed  being  that,  as  the  cocks,  except  while  oil  is  be- 
ing drawn,  are  always  in  the  air,  there  is  no  danger  of  leak- 
age of  this  subtile  fluid. 

Fig.  24. 


207 


Lantern  for  electric  light. 

Barbier  &  Fenestre  have  purchased  from  Captain  Doty  Doty  burner, 
his  patent  for  mineral-oil  burners,  (see  Fig.2,Plate  XXXVI,) 
except  as  regards  Great  Britain  and  the  United  States,  where 
he  reserves  the  right,  and  the  French  government,  with 
which  he  has  made  special  arrangement.  They  state  that 
they  are  making  mineral-oil  lamps  for  light-houses  in  all 
parts  of  the  world,  and  that  mineral-oil  has  been  adopted  in 
most  countries  of  Europe,  as  well  as  in  South  America  and 
Canada.  All  the  lens-manufacturers  were  busy  in  fitting  the 
colza-oil  lamps  of  the  French  light-houses  for  the  use  of  min- 
eral oil. 

A  variation  of  one  millimeter  (^§- of  an  inch)  in  the  height 
of  the  overflow  in  winter  and  summer  is  provided  for. 

The  tops  of  all  burners  made  by  French  lens-makers  are    copper    tmrn- 
of  copper.    I  suggested  to  one  of  them  that  we  had  found ers> 
iron  to  be  much  more  durable,  and  he  concurred  in  the  opin- 


208  EUROPEAN    LIGHT-HOUSE    SYSTEMS 

ion  that  iron  would  iiot  submit  as  readily  as  copper  -to  the 
destructive  action  of  the  flame. 

Lanterns  and  lenses  are  differently  constructed  for  differ- 
ent countries,  some  preferring  the  diagonal  bars,  on  ac- 
count of  the  less  obstruction  to  the  light,  and  others  prefer- 
ring the  vertical  ones,  on  account  of  the  greater  economy. 
The  difference  in  cost  between  the  two  kinds  of  lenses  was 
stated  to  be  for  the  first  order  about  1,000  francs,  ($200.) 

Lenses   suited     Lenses  are  made  to  suit  the  height  above  the  sea-level  at 
aboveirethe  awL  which  the  different  orders  are  usually  placed,  and  any  ex- 
cess of  such  height  requires  special  calculations  and  adjust- 
ments.    Unless  otherwise  stated,  the  height  at  which  a  first- 
order  lens  is  to  be  placed,  is  supposed  by  the  makers  to  be 

Photometer  bet  ween  150  and  200  feet  above  the  sea.    The  photometer 

used  by  all  the  lens-makers  in  Paris  is  the  same  as  I  have 

described  as  in  use  at  the  Depot  des  Phares.    I  was  informed 

.    that  most  countries  use  the  "  mechanical  lamp  "  for  the  first 

.Lamps  used,  tor 

different  ordersof  and  second  orders  of  lights,  the  "  moderator"  for  third  and 

hgbts. 

fourth  orders,  and  common  (capillary  attraction)  lamps  for 
the  fifth  and  sixth  orders,  but  that  the  sixth-order  lamp  is 
little  used. 

I  found  the  members  of  the  several  firms  all  to  be  cour- 
teous and  intelligent  gentlemen,  and  my  experience  with 
them  at  their  offices  and  manufactories  confirmed  the  high 
opinion  I  had  previously  entertained,  and  which  were  de- 
rived from  my  correspondence  with  them  and  from  the  ex- 
cellent quality  of  the  apparatus  furnished  to  us. 

1  should  state,  before  concluding  my  notes  in  regard  to  Paris, 
that  Mr.  Washburne,  the  American  Minister,  was  absent 
at  the  time  of  rny  visit.  I  am,  however,  under  obligations 
to  Colonel  Hoffman,  the  secretary  of  legation,  for  his  valu- 
able assistance. 

[Translation.] 

REMARKS  ON  BURNERS  EMPLOYED  FOR  LIGHT-HOUSE  ILLU- 
MINATION. 

BY  HENRY-LEPAUTE  BROTHERS. 

In  all  countries  in  the  world  burners  with  concentric  wicks 
are  used  in  light-house  apparatus,  the  number  of  wicks 
varying  from  one  to  four,  according  to  the  order  of  the  lens. 
These  burners  were  invented  in  1821,  on  the  principle  of 
burSeVrsnti0wit°hf  those  of  Argand,  by  MM.  Augustin  Fresnel  and  Arago. 
concentric  wicks,  j,^  concentric  wicks  are  separated  by  air-spaces  for  supply- 
ing the  oxygen  necessary  for  good  combustion. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


209 


The  conditions  fulfilled  by  the  ordinary  Fresnel  burners 
are  the  following  : 


Order  of  lens. 

Number 
of  wicks. 

Dimensions  of  fully  devel- 
oped flames. 

Luminous  in- 
tensity in 
Carcel  units. 

Maximum  di- 
ameter. 

Height  taken 
from 
the  burner. 

First                               

4 
3 
2 
2 
1 
1 

Millimeters. 
90 
75 
45 
38 
30 
27 

Millimeters. 
100 
80 
70 
65 
45 
37 

23 
15 
5 
3 
1.6 
1.3 

Third 

Fourth           

Fifth 

Sixth                    

Table  of  ordin- 
ary Fresnel  burn- 
ers. 


I  n  t  e  n  s  ity  of 
burner  of  1845. 


Ill  examining  this  table  it  will  be  noticed  that  third-order 
apparatus,  interior  diameter  one  meter,  is  lighted  by  two- 
wick  burners,  differing  but  little  from  those  employed  in 
fourth-order  apparatus,  the  interior  diameter  of  whose  op- 
tical part  is  but  half  a  meter. 

In  1845  M.  Henry-Lepaute,  Sr.,  who  had  been  a  colaborer    Efforts  of  M. 

J  Henry  -  Lepaute, 

in  the  experiments  and  construction  of  the  apparatus  de-  sr.,to'mcreasethe 

power   of   burn- 

Signed  and  calculated  by  M.  Augustin  Fresnel,  sought  to  ers. 

apply  to  third-order  lenses  more  powerful  burners  than  those 

then  in  use.    After  his  own  drawings  he  then  had  made,    Burner  of  i845. 

by  M.  Blazy-Jal  lifter,  a  two-wick  burner  of  special  construc- 

tion.   The  two  wicks,  respectively  54  and  28  millimeters  in 

exterior  diameter,  were  separated  by  a  double  air-space, 

and  an  air-tube  was  placed  around  the  larger  wick.     These 

air-tubes  were  elongated  and  enlarged  below,  and  the  chim- 

ney-holder slipped  over  the  outside.    This  burner  gave  an 

intensity  of  from  four  to  five  Carcel  units,  and  consumed 

200  grams  of  colza-oil  per  hour.     Some  experiments  were 

made  in  1845  in  the  workshops  of  M.  Heury-Lepaute,  Sr., 

and  M.  Leonor  Fresnel,  engineer  of  the  corps  des  ponts  et 

chaussees  and   director  of  the  French  light-house  service, 

verified  the  principal  results  by  one  of  his  assistants.    These    Adoption    of 

n.   ,1       TL-T     i          burner  of  1845  by 

new  burners  were  adopted  by  the  kingdom  of  the  Nether-  kingdom  of  the 
lands  for  the  light-houses  of  Brouwershaven,  (1845-1847,) 
Scheveningen,  (1851,)  Renesse,  and  Schiermonikoog.  The 
French  government,  while  recognizing  the  merits  of  these 
burners,  did  not  adopt  them,  not  wishing  to  alter  the  standard 
burners  invented  by  Messrs.  Fresnel  and  Arago.  For  this 
reason  M.  Henry-Lepaute  continued  to  make  them  only 
when  specially  ordered. 

In  1868  the  question  of  the  use  of  mineral-oil  in  light- 

houses  was  brought  up.    Previous  experiments  had  Bot 

given  very  good  results.    An  American,  Mr.  Doty,  pro- 

posed  a  form  of  burner  which  succeeded  quite  well  for 

S.  Ex.  54  -  14 


Question  of  the 


Doty  burner. 


210 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


schist-oils,  but  its  arrangement  and  dimensions  differed  from 
the  standard  which  the  light-house  administration  had  not, 
E  xP  eriments  up  to  that  time,  consented  to  modify.  About  that  period  we 
were  making  numerous  experiments  relating  to  the  burning 
of  mineral-oil,  and  after  many  attempts  we  succeeded  in 
constructing  a  burner  with  air- tubes  enlarged  below,  and 
with  a  tube  exterior  to  the  large  wick.  The  arrangement 
was  almost  identical  with  that  of  the  1845  burner  invented 
by  our  father,  except  that  the  air-space  between  the  wicks 
was  not  double.  We  then  experimented  with  the  1845 
burner,  feeding  it  with  mineral-oil,  and  found  the  combus- 
tion very  satisfactory, 
invention  of  In  1869  we  invented  the  truncated-cone  burner,  preserv- 

bum?r?i869.'c°neing  exactly  the  dimensions  of  the  Fresnel  burner  for  lights 

of  all  orders.    Specimens  of  these  burners  were  sent  in  1869 

to  the  light-house  administrations  of   Sweden,  Norway, 

comparison  Denmark,  the  United  States,  and  Brazil.    The  French  ad- 

bvurnerthe  )oty  ministration  tried  our  truncated-cone  burners,  comparing 
them  with  the  Doty,  and  found  them  always  equal,  and 
sometimes  superior,  especially  the  one-wick  burner.  Still 
they  charged  us  to  try  to  modify  the  Fresnel  burner  so  that 
with  the  same  general  arrangement,  it  might,  by  means  of 
some  additions,  be  used  for  mineral-oils. 

The  experiments  undertaken  in  1872  succeeded,  and  we 
fixed  upon  the  arrangement  of  the  new  modified  Fresuel 
burners  of  1873,  which  are  now  being  substituted  for  the 
ordinary  Fresnel  burners,  so  that  schist-oil  may  be  used  in 
all  light-houses  of  France.  The  success  of  these  burners  is 
due  in  a  great  measure  to  the  addition  of  an  exterior  air- 
tube,  as  in  the  1845  burner ;  an  arrangement  also  used  by 
Mr.  Doty  in  his  burners. 

In  fine,  all  schist  burners  now  in  use  are  reproductions 
of  the  burner  invented  in  1845  by  M.  Henry-Lepaute,  Sr., 
still  in  actual  use  in  a  large  number  of  light-houses  in  Hol- 
land. The  conditions  fixed  by  the  French  administration 
for  the  dimensions  and  intensity  of  the  new  modified  Fres- 
nel burners  are  the  following : 

Table  of  modified  burners. 


Modification  of 
the  Fresnel  burn- 
er, 1872. 


Exterior 
tube. 


Table  of  modi- 
fied burners. 


Order  of  lens. 

^ 

z& 
If 
& 

Dimensions  of  the  fully 
developed  flame. 

Luminous  in- 
tensity in 
Carcel  units. 

Maximum 
diameter. 

Height 
taken  from 
the  burner. 

First                       

5 
4 
3 
2 
1 
1 

Millimeters. 
105 
85 
65 
45 
25 
25 

Millimeters. 
110 
90 
80 
70 
45 
45 

30 
23 
14 
6.4 
2.2 
2.2 

Third                                     

Fourth                                                          

Fifth.                                      

Sixth                    

-  n 
2  x 

§5 


2 

c 


- 


n  co 


"o  r" 
fn 

n 

r 


EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


211 


It  will  be  seen  that  above  the  fifth  order  the  number  of   increase     i  n 

,         ,  .  i        mi  •     ±1  i  ^    -        t  number  of  wicks. 

wicks  has  been  increased.  There  is  thus  obtained  a  greater 
intensity  and  more  horizontal  divergence,  and  as  schist  is 
cheaper  than  other  oil  the  expense  of  illumination  is  not 
increased. 

The  following  table  clearly  shows  the  differences  between 
the  old  and  new  systems : 

Comparative  table  of  the  dimensions,  consumption,  and  intensities  of  the  bur- 
ners employed  in  the  French  light-house  service. 


Table  of  differ- 
ences. 


Order  of  light. 

Number  of  wicks. 

Outer  diameter  of  wicks  in 
inches. 

Consumption 
per  hour. 

1 

.22 
•3 

a 
2 

i 

ci 

n 

i 

d 

« 

In  grams. 

In  fluid  oz.* 

ORDINARY  COLZA-OIL 
BURNERS. 

First  order 

4 

a 

2 
2 

1 
1 

5 
4 

0.98 
1.10 
0.94 
0.83 

1.10 
0.94 

.18 

.18 

1.85 
1.97 
1.73 
1.50 

2.68 
2.91 

3.54 

760 
500 
175 
110 

60 
50 

900 
630 
360 
160 
55 
55 

28.46 
18.73 
6.55 
4.12 

2.25 

1.87 

37.42 
26.20 
14.97 
6.65 
2.29 
2.29 

23 
15 
5 
3 

1.6 
1.3 

30 
23 
14 
6.4 
2.2 
2.2 

SocAnd  order    

Third  order,  (large  size) 
Fourth    order,    (third 
order  small  size.) 
Fifth    order,     (fourth 
order  large  size.) 
Sixth    order,    (fourth 
order  small  size.) 

MODIFIED  FRESXEL  BUR- 
NER FOR  MINERAL-OILS. 

First  order 

1.97 
1.97 

2.75 
2.75 
2.75 

3.54 
3.54 

4.33 

Second  order  

Third  order 

3 

2 
1 

1 

.18 
.18 
.18 

.18 

1.97 
1.97 

Fourth  order  

Fifth  order 

Sixth  order  

*  128  fluid  ounces  to  the  wine-gallon. 

NOTE.— The  intensities  obtained  by  burning  colza-oil  in  the  modified  Fresnel  bur- 
ners are  as  nearly  as  possible  the  same  as  those  given  by  mineral-oils. 


212  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 


burner  Fig.  1  of  Plate  XXXIII  shows  the  arrangement  of  the  air- 
tubes  and  wicks  in  the  ordinary  Fresuel  burners.  The 
ascent  and  overflow  of  the  oil  is  also  shown. 
45paute  ri^  ^  Plate  XXXVI,  shows  the  arrangement  of  the  two- 
wick  burner  invented  in  1845  by  M.  Henry-Lepaute,  Sr.  It 
will  be  seen  that  the  air-tubes  are  longer  and  enlarged 
below;  it  will  also  be  remarked  that  the  tube  between  tjie 
wicks  is  double.  In  all  these  burners  the  wicks  are  lowered 
and  raised  by  racks  and  pinions. 

caFyllbm™erConof     ^^'  ^'  Plate  XXXIII,  shows  the  arrangement  adopted  in 

iienry-Lepaute,  our  1869  burners.    All  the  air-tubes  are  elongated  below, 

increasing  in  diameter.    There  is,  as  in  the  1845  burner,  an 

exterior  tube,  and  a  disk  is  placed  in  the  center  of  the 

burner  when  mineral-oils  are  burned. 

Modified  Fres-  Fig.  3,  Plate  XXXIII,  shows  the  form  proposed  by  us  and 
adopted  by  the  French  administration  for  all  French  lights. 
The  air-  tubes  are  arranged  as  in  the  ordinary  Fresnel 
burner.  There  is  also  an  exterior  tube  shorter  than  the 
others.  The  chimney-holder  is  shorter  than  in  the  ordinary 
burner,  and  there  is  a  disk  moved  by  a  rack  and  pinion, 
which  is  necessary  when  burning  mineral-oil.  All  the  new 
burners  are  made  of  copper. 


rSeofib  hi°Vurn"     In  l3urners  fed  with-  mineral-oil  the  oil  should  rise  to  from 


35  to  00  millimeters  below  the  crown  of  the  burner,  on  ac- 
count of  the  volatility  of  these  oils.  It  is  the  same  when  a 
constant-level  lamp  is  used.  Furthermore,  it  is  necessary 
that  this  level  should  be  raised  or  lowered  in  the  same 
burner,  according  to  the  nature  of  the  oil  and  the  surround- 
ing temperature. 

Two  kinds  of  methods  are  employed  for  varying  the  level 
of  the  oil. 

1ST.  LEVEL  VARIED  BY  APPLIANCES  IN  THE  INTERIOR  OF 
THE  BURNER. 

Level  varied  by     Whether  the  Henrv-Lepaute,  the  clock-work,  or  the  mod- 

an  interior  appa-  -  ..     ..  , 

erator  lamp  is  used,  an  excess  of  oil  cannot  be  entirely  sup- 


pressed, and  there  should  be  a  means  of  varying  the  level 
in  the  burner  itself. 

Level  varied  in     ^n  the  Doty  burner,  (see  Fig.  2,  Plate  XXXVI,)  an  ap- 

thel)otyburuer-  pendage  for  this  purpose  is  attached  to  the  outside  of  the 

cistern.*     This  has  the  disadvantage  of  being  fragile,  and 

*  By  the  following  communication,  which  I  have  recently  received 
from  M.  Lepaute,  it  would  seem  that  the  French  government  has  decided 
to  use  this  appendage  : 

"A  modification  has  been  made  in  mineral-oil  lamp-burners  for  the- 
purpose  of  regulating  the  supply  of  oil.  This  modification  consists  of 


n 
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n 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

obscures  the  light  in  one  direction.  All  the  systems  pro- 
posed by  us  are  for  the  interior  of  the  burner,  and  have  been 
used  with  success  since  1869. 

In  the  modified  Fresnel  burners,  (Fig.  1,  Plate  XXXIV,) 
the  oil  overflows  into  a  central  tube,  which  can  be  length- 
ened by  means  of  short  sections  (B)  screwed  on.  These  are 
of  determinate  lengths,  and  are  fixed  in  place  by  a  wrench, 
(A,  Fig.  1.) 

When  it  .is  required  to  burn  vegetable  or  animal  oil  with 
an  overflow,  the  tube  is  stopped  by  a  cap,  (C.)  A  friction- 
stem  carries  the  disk.  These  various  operations  cannot  be 
performed  when  the  burner  is  lighted,  and,  besides  this 
disadvantage,  the  level  of  the  oil  can  be  varied  only  by  a 
considerable  amount,  which  must  be  determined  in  ad- 
vance. In  France,  where  the  temperature  is  moderate,  and 
only  paraffine  is  used,  these  disadvantages  are  not  great,  but 
they  would  be  serious  if  the  burners  were  used  where  the 
temperature  varied  greatly  and  for  all  kinds  of  mineral-oils. 

We  use  two  other  methods  by  which  the  level  of  the  oil 
and  that  of  the  disk  can  be  varied  while  the  burner  is  lighted. 

In  the  arrangement  shown  in  Fig.  2,  Plate  XXXIV,  a    slide  valve sys- 
double  oil-tight  envelope  is  placed  inside  the  central  wick- te 
tube,  and  the  tube  is  pierced  with  a  longitudinal  slit  through 
which  the  oil  flows.    This  slit  is  closed  by  a  slide-valve 
raised  and  lowered  by  a  rack  and  pinion,  the  stem  of  which 
passes  through  a  packed  chamber.    When  the  slide  is 
raised  entirely  it  closes  the  slit,  and  vegetable  or  animal  oil 
can  then  be  burned  with  an  overflow.    The  disk  is  carried 
by  a  guide-stem  placed  in  the  central  air-tube  and  moved 
by  a  rack  and  pinion. 

In  the  arrangement  shown  by  Fig.  3,  Plate  XXXIV,  the   Telescopic-tube 
overflow  of  oil  is  managed  the  same  as  in  the  modified  Fres- 8ys 
nel  burners  except  that  the  overflow-tube  is  lengthened  by 
an  interior  sliding  tube  worked  by  means  of  a  rack.    The 
disk  is  moved  by  a  rack  and  pinion  passing  into  the  over- 
flow tube  and  through  a  packed  chamber  which  prevents 
the  leakage  of  oil. 

an  appendage  added  to  these  burners,  and  which  constitutes  a  constant- 
level."  (It  is  represented  in  Fig.  5,  Plate  XXXV.) 

"The  two  solid  caps  which  accompany  each  burner  are  intended  to  be 
used  in  case  it  is  necessary  to  have  recourse  to  colza-oil;  the  cap  with 
the  wire-cloth  (toile  mtialliquc)  is  used  to  cover  the  three  tubes  when 
mineral-oil  is  used. 

"With  burners  thus  modified  the  overflow  need  not  be  limited  to  a 
few  drops,  as  heretofore  required." 

This  seems  to  me  an  excellent  arrangement,  and  not  subject  to  the  ob- 
jections mentioned  by  M.  Lepaute.— [G.  H.  E.J 


214  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

2D.   LEVEL  VARIED   BY  EXTERIOR   MEANS. 

These  various  systems  of  our  invention  can  be  applied  to 
System  for  rais- all  the  orders.  The  oldest  and  most  simple,  Fig.  1,  Plate 
XXXV,  is  applicable  to  apparatus  of  the  sixth,  fifth,  and 
fourth  orders,  in  which  the  lamp  with  its  cistern  is  attached 
to  the  interior  of  the  lens.  The  bottom  of  the  cistern  regu- 
lates the  level  of  the  oil  in  the  burner,  and  a  graduated 
scale  shows  the  amount  of  variation.  The  valve-stem  is 
long  enough  to  always  raise  the  valve  from  the  mouth  oi' 
the  cistern.  Where  the  capacity  of  the  lamp  is  greater,  the 
cistern  is  carried  by  a  sliding  armature  (Fig.  2,  Plate  XXXV) 
moved  by  a  rack  fixed  to  one  of  the  uprights  of  the  appa- 
ratus or  the  lantern,  and  the  level  is  established  in  an  open 
vessel  fixed  at  the  height  of  the  focal  plane,  and  is  regulated 
by  the  mouth  of  the  neck  of  the  cistern. 

In  these  two  systems  the  cisterns  are  hermetically  closed, 
and  they  must  be  raised  arid  inverted  to  be  filled  unless 
they  are  furnished  with  a  movable  plug  at  their  upper  part. 
To  obviate  this  inconvenience,  which  is  quite  serious  when 
the  lamp  is  of  great  capacity,  we  employ  various  means. 

In  tne  system  shown  by  Fig.  3,  Plate  XXXV,  the  level 
pieces.  js  established  in  an  enlarged  part  of  the  conduit  in  which 

loosely  enters  the  end  of  the  oil- tube,  on  which  a  screw- 
thread  is  cut.  On  this  an  extension-piece  slips,  the  lower- 
ing or  raising  of  which  varies  the  level  as  indicated  by  a 
graduated  scale  $  a  cock  above  shuts  off  the  oil  when  the 
screw-plug  in  the  upper  part  of  the  cistern  is  opened  for 
filling. 
System  with  an  in  the  svstem  shown  by  Fig.  4,  Plate  XXXV,  the  air- 

inclepeudent  air- 
tube  and  sliding  tube  is  prolonged    to  the    top  of  the    reservoir,  and    is 

extension-p  i  e  c  e 

moved  by  a  rack,  lengthened  at  will  at  the  bottom  by  a  sliding  t ube  moved 
by  an  exterior  rack.  Another  rack  moves  the  valve  down 
into  its  socket,  and  thus  shuts  off  the  descent  of  the  oil 
when  the  reservoir  is  being  filled.  These  last  two  systems 
take  but  little  space,  and  are  very  simple  and  easy  to  re- 
pair. All  these  systems  have  been  in  use  in  Sweden,  Nor- 
way, and  France  for  several  years. 

Recapitulation.  To  recapitulate,  the  requirements  for  burning  mineral-oil 
are :  special  burners  with  powerful  currents  of  air,  means 
of  varying  the  level  of  the  oil  in  the  burner  according  to 
the  surrounding  temperature  and  the  nature  of  the  oil,  and 
means  of  raising  and  lowering  the  central  disk,  which  sends 
air  into  the  interior  of  the  central  flame. 

Smoke-funnels.  ^ur  experiments  have  induced  us  to  modify  the  form  of 
smoke-funnels  (fumivores)  and  dampers,  and  to  adopt  the 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  215 

forms  represented  by  Fig.  4,  Plate  XXXVI.  The  glass 
chimney  is  surmounted  by  a  copper  continuation  of  the  same 
diameter,  which  sets  into  the  damper.  The  latter  is  cylin- 
drical, with  a  spherical  part  midway  of  its  length,  in  which 
the  register  moves.  A  series  of  cylindrical  smoke-funnels 
of  increasing  diameter,  terminated  below  by  truncated  cones, 
completes  the  chimney.  The  annular  spaces  between  the 
various  funnels  introduce  air,  and  by  cooling  the  smoke 
render  the  combustion  more  complete  and  the  draught  more 
regular.  The  enlargement  of  that  part  of  the  damper  where 
the  register  is  placed  prevents  the  contraction  of  the  orifice 
by  which  the  smoke  escapes.  This  arrangement  is  the  best 
for  burners  with  five,  four,  and  three  wicks,  but  it  is  not 
indispensable  for  burners  of  two  wicks  and  one  wick. 

The  principle  of  the  cylindro-conical  burners  with  outer    concentric  gas- 
air- tube  has  permitted  us  to  construct  gas-burners  with  con- bl] 
centric  crowns  giving  very  satisfactory  combustion.    Fig.  3, 
Plate  XXXVI,  shows  the  arrangement  of  a  four-crown 
burner.    It  will  be  remarked  that  each  of  the  crowns  is  fed 
at  the  two  extremities  of  the  same  diameter,  and  that  a 
special  cock  regulates  the  flow  of  gas  to  each  crown.    These 
burners  have  worked  very  well,  and  do  not  heat  to  any  great 
degree. 

REMARK. — Fig,  3,  Plate  XXXIII,  shows  that  the  chimney 
of  the  modified  Fresnel  burners  is  supported  on  a  plate  by 
means  of  three  ears.  This  system,  adopted  by  the  French 
administration,  has  the  disadvantage  of  great  instability ; 
the  chimney  cannot  be  exactly  centered  on  the  burner  5  be- 
sides, the  chimneys  not  being  exactly  set  below,  there  are 
no  means  of  getting  them  quite  perpendicular.  We  prefer 
the  use  of  the  old  chimney-holders  with  movable  grates  on 
the  inside,  by  means  of  which  the  chimney  can  be  exactly 
centered  and  solidly  held. 

LIGHT-HOUSES  AT   THE  MOUTH  OF  THE   SEINE 

When  at  the  Depot  des  Pliares,  M.  Allard  kindly  gave  me 
a  letter  to  M.  Arnoux,  the  engineer  (des  ponts  et  chaussees,) 
who  is  in  charge  of  the  administration  of  all  public  works 
(including  the  light-houses)  on  the  left  bank  of  the  Lower 
Seine,  aud  I  proceeded  by  rail  through  Normandy  to  Hon- 
fleur,  stopping  at  Eouen  to  see  that  ancient  city,  and  espe- 
cially the  interesting  antiquities  in  its  celebrated  museum. 

M.  Arnoux  received  me  with  great  politeness,  and  I  had 
an  excellent  opportunity  of  inspecting  the  lights  of  PHdpital 
and  Fatouville,  and  the  pier-light  at  Honfleur. 


216  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


n   the     The  light-keepers  in  the  French  service  are  known   as 
horuse  service?  *"  masters  (maitres  dephare)  and  keepers,  (gar  diem.) 
of  keepers!1  ment     The^  are  appointed  by  the  prefect  or  chief  civil  officer  of 
the  department  on  the  nomination  of  the  engineer  of  the 
district,  who  is  charged  with  the  river  and  harbor  works, 
including  the  light-houses.    Men  who  have  served  as  sol 
diers  and  sailors  are  given  the  preference. 

For  appointment  the  following  requisites  are  necessary  : 

1st.  They  must  be  French,  and  between  twenty-one  and 
forty  years  of  age. 

2d.  They  must  be  free  from  all  infirmities  which  would 
prevent  an  active  daily  life. 

3d.  They  must  present  a  certificate  of  good  moral  char- 
acter. 

4th.  They  must  know  how  to  read  and  write,  and  have 
an  elementary  knowledge  of  arithmetic. 

salaries.  The  annual  salary  of  masters  of  lights  is  fixed  at  1,000 

francs,  ($200.)  The  ordinary  keepers  are  divided  into  six 
classes,  salaried  as  follows:  First  class,  850  francs,  ($170;) 
second  class,  775  francs,  ($155;)  third  class,  700  francs, 
($140  ;)  fourth  class,  625  francs,  ($125  ;)  fifth  class,  550  francs, 
Fuel  and  ra-  ($110  ;)  sixth  class,  475  francs,  ($95.)  There  is  also  allowed 
to  each  master  and  keeper  a  certain  quantity  of  wood  or  coal 
for  heating  purposes/and  the  master  and  keepers  of  lights 
isolated  by  the  sea  receive  indemnities  for  sea-rations. 

The  salaries  and  indemnities  are  paid  monthly.  Fuel  is 
furnished  in  kind  and  according  to  the  decision  of  the  engi- 
neers. Salaries  of  masters  and  keepers  are  subject  to  a  de- 
duction of  5  per  cent.,  and  these  employes  are  entitled  to 
retiring  pensions  derived  from  this  fund.  An  oath  must 
be  taken  by  masters  and  keepers  immediately  after  their 
appointment  in  order  that  they  may  be  held  responsible,  if 
any  dereliction  is  committed  in  the  establishment  to  which 
they  are  attached. 
Number  of  ^De  number  and  classes  of  keepers  attached  to  each  light 


aordSs  is  nxed  ^v  ministerial  decision  on  the  recommendation  of 
oi  lights.  the  engineer,  approved  by  the  prefect  and  the  director  of  the 

light-house  service.  The  number  is  never  less  than  three 
for  first-order  lights,  and  two  for  those  of  the  second  and 
third  orders. 

Maitres  des     Tlie  masters  are  charged  with  the  supervision  of  the  serv- 

phares.  jce  of  severai  lights  or  beacons.    The  title  (maitre  de  phare) 

can  also  be  granted  to  those  of  the  principal  keepers  (chefs 

gardiens)  who  have  merited  it  by  exceptional  service.    At 

the  lights  served  by  several  keepers  and  where  there  is  no 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  217 

master  one  of  the  former  takes  the  title  of  principal,  (chef.) 
In  case  of  his  absence  the  second  keeper  takes  his  place. 

The  masters  and  principal  keepers  are  particularly  respon- 
sible for  the  entire  service  of  the  lights  and  the  receipt  of 
supplies.  They  are  charged  with  the  keeping  of  the  regis- 
ters and  the  correspondence. 

The  other  keepers  owe  obedience  to  the  master  in  every- 
thing that  concerns  the  service,  but  have  the  right  of  appeal 
to  the  engineer. 

The  principal  keepers  assist  in  cleaning  the  apparatus, 
and  take  their  watch  the  same  as  the  others. 

The  masters  are  not  held  to  this  service,  but  they  are  re- 
quired to  visit  the  light  at  least  twice  each  night,  and,  by 
decision  of  the  engineer,  they  can  be  ordered  to  temporarily 
perform  the  duties  of  principal  keeper  when  circumstances 
render  it  necessary. 

Every  year,  on  recommendation  of  the  engineer-in-chief,    Bonus  paid  to 
a  bonus  not  exceeding  a  month's  salary  may  be  allowed  by  eServ 
the  prefect  to  the  most  meritorious  keepers,  the  number  re- 
ceiving such  bonus  not   to  exceed  one-fifth  of  the  total 
number  of  keepers  in  the  department.    Masters  and  keepers 
may  be  punished  or  removed  by  the  prefect^  on  the  report 
of  the  engineer-in-chief. 

The  service  of  beacons  of  secondary  importance  may  be    service  of  infe- 
confided  to  persons  who  are  not  regularly  in  the  light-house rior  bcacous 
service. 

PHARE  DE  L'HOPITAL. 

This  light,  so  named  from  its  proximity  to  the  ancient 
hospital  at  Honfleur,  is  of  the  third  order,  fixed.    It  is  a 
handsome  structure  of  granite,  and  on  both  the  exterior    Description. 
and  interior  no  expense  has  been  spared  in  the  way  of 
architectural  effect  and  fine  finish. 

The  entrance  is  very  imposing,  and  bears  above  it  the 
inscription,  "  Stella  Maris."  The  interior  of  the  structure 
is  lined  with  granite  ;  although  there  is  no  air-space  in  the 
interior  of  the  walls,  they  appeared  to  be  perfectly  dry. 

Directly  below  the  watch-room  is  a  bed-room,  furnished    sleeping  -  room 
with  a  neat  bed  with  hangings  and  other  furniture,  for  the in  tower 
occupation  of  the  keeper  not  on  watch,  for  it  is  a  rule  of 
the  French  service  that  there  must  be  always  two  keepers 
in  the  tower  during  the  exhibition  of  the  light.    In  cases 
where  there  are  three  keepers  at  a  station,  one  of  them  can 
remain  with  his  family  at  the  dwelling,  but  when  there  are 
but  two  keepers,  neither  can  absent  himself  from  the  tower 
at  night. 


218  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

watch-room.  The  watch-room  at  this  station  was  neatly  furnished  with 
a  table  and  easy  chairs,  and  was  nicely  paved  and  lined 
with  a  pretty  imitation  of  variegated  marble. 

^Keepers  dwell-  rphe  dwelling,  which  is  at  some  distance  from  the  tower, 
is  also  a  handsome  building,  with  neatly  painted  walls  and 
ceilings.  Each  keeper  is  allowed  a  kitchen  and  two  bed- 
rooms, besides  certain  standing  furniture,  as  in  the  English 
service  ;  and  a  list  is  framed  and  hung  in  each  room  show- 
ing what  furniture  therein  belongs  to  the  government  and 
the  principal  keeper  is  responsible  for.  This  furniture,  made 
of  hard  wood,  is  strong  and  durable. 

The  family  is  not  recognized  in  the  supply  of  furniture, 
the  kitchen  and  one  bed-room  only  for  each  keeper  being 
furnished  by  the  government. 

Rooms  fitted  tip     In  the  dwelling  are  also  fitted  up  rooms  for  the  engineer 

tor   district    offi-     „     .,        _.    .    .    .  ,  .    . 

cers.  of  the  district  and  one  for  the  conducteur,  (assistant  engi- 

ciutiesV.110  'ur>  neer,)  who  is  a  subordinate  of  the  engineer,  and  whose  espe- 
cial business  it  is  to  attend  to  the  lights  of  the  district, 
taking  care  that  they  are  properly  exhibited  and  the  build- 
ings and  lenticular  apparatus  kept  at  the  highest  state  of 
order  and  efficiency,  while  the  engineer  exercises  a  general 
supervision. 

Number  of  There  are  at  this  light  three  keepers;  one  of  them  has  the 
title  of  maitre  de  pliare  and  the  other  two  are  cliefs-gardiens, 
all  of  higher  rank  and  rate  of  pay  than  ordinary  keepers. 
These  ranks  they  had  attained  by  long  and  faithful  service. 
It  should  be  noted  that  in  the  French  light-houses  the 
keepers  are  not  promoted  and  changed  from  station  to  sta- 
tion, as  in  the  English  service,  but  have  a  chance  for  pro- 
motion only  at  the  stations  to  which  they  are  first  appointed. 
Mineral -on  to  At  the  date  of  my  visit  the  illumiuant  at  the  Pliare  de 
VHdpital  was  colza,  but  mineral-oil  and  a  lamp  for  its  use 
had  been  received  at  the  station,  and  orders  to  make  the 
change  of  lamps  and  illuminants  were  daily  expected. 

The  mineral-oil  was  to  be  kept  in  the  store-room  at  the 
dwelling,  in  wooden  reservoirs  lined  with  zinc,  and  I  found 
that  the  French  use  much  less  precaution  in  storing  it  than 
do  the  English,  who  are  building  detached  vaulted  maga- 
zines of  masonry  for  this  purpose.  The  English  also  use 
sheet-iron  cans  or  butts  for  reservoirs  as  a  substitute  for 
tin,  which  is  not  considered  as  good  for  the  preservation  of 
the  oil. 

FEU  DE  PORT  AT  HONFLEUR. 

This  is  a  small  pier  light-house  of  granite,  with  the  focal 
plane  20  feet  above  the  base,  and  shows  a  red  light  from  a 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  219 

lens  of  the  sixth  order,  when  there  are  two  meters  of  water 
upon  the  bar.    The  illuminaut  was  mineral-oil,  and  the  lamp,    niuminant  and 
as  in  all  the  smaller  orders  of  light-houses  in  France,  one  of  a 
the  "  Maris"  pattern,  the  oil  being  drawn  up  by  capillary 
attraction.    The  watch-room  is  neatly  furnished  with  three 
linen-covered  easy  chairs,  a  table,  and  curtained  bed. 
The  floor  of  the  main  gallery  was  of  stone,  as  was  the    stone  floor  to 

.  ,  . ,  .  i       j?  -i  the    gallery,  and 

parapet ;  a  convenient  width  was  given  to  the  former  by  pro-  extension  to  the 

jectiug  the  iron  railing  about  six  inches  beyond  the  cornice sa 

of  the  tower,  a  simple  mode  of  obtaining  space  around  the 

lanterns  of  small  towers.    The  keeper's  dwelling  is  a  neat 

stone  structure  standing  near  by  on  the  pier.    The  keeper, 

there  being  but  one  at  this  station,  takes  care  of  the  light 

and  also  attends  to  the  tide-signals. 

I  found  at  the  different  light- stations  which  I  visited,  in 
Great  Britain  as  well  as  in  France,  that  the  keepers  readily 
accepted  small  gifts  of  coin  in  consideration  of  their  services 
in  showing  their  light-houses  to  visitors,  and  I  asked  the 
conductcur  at  Honfleur  whether  any  regulation  on  the  sub- 
ject existed.  He  informed  me  that  the  acceptance  of  small 
sums  from  visitors  is  not  forbidden,  their  service  differing 
in  that  respect  from  our  own  ;  and  it  may  be  well  to  ques- 
tion whether  our  regulation  in  this  respect  should  not  be 
abolished,  as  it  is  constantly  violated  and  is  productive  of 
no  good. 

PHARE  DE   FATOTJVILLE. 

This  light,  which  is  of  the  first  order,  is  situated  on  a  high 
hill  on  the  left  bank  of  the  Seine,  three  leagues  above  Hon- 
fleur, and  forms,  with  the  Phare  de  VHopital  a  range  or  "  lead" 
to  guide  clear  of  the  "Batier  "  Shoals,  ten  miles  distant  from 
Honfleur.  It  is  under  the  general  superintendence  of  the 
engineer  at  Rouen.  The  tower  is  of  stone,  octagonal  in  Description  of 
plan,  with  keepers'  dwellings  on  each  side  connected  with  it to 
by  passages  at  each  story.  The  entrance  to  the  tower  is 
quite  imposing,  the  visitor  entering  a  large  furnished  polyg- 
onal hall  from  which  a  clear  view  of  the  interior  of  the  tower 
to  the  lantern  is  afforded. 

There  are  three  keepers,  (one  maitre  de  phare  and  two    Keepers. 
gardiens  of  second  class,)  two  of  whom  are  on  duty  at  night, 
the  other  having  the  day-watch. 

The  night-keepers  alternate  in  the  service  of  the  light, 
one  being  on  watch  in  the  tower  while  the  other  sleeps  in 
the  room  below. 

The  gardien  who  conducted  me  about  the  establishment 


220  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

stated  that  he  had  been  more  than  twenty  years  in  the  serv- 
ice, and  much  longer  terms  are  not  infrequent. 

^  iiiuminant  ana  The  lamp  in  use  at  the  time  of  my  visit  was  a  mechanical 
or  pump  lamp,  burning  colza-oil.  The  burner  had  an  adjust- 
able chimney  to  regulate  the  access  of  the  outer  current  of 
air  to  the  flame,  but  it  had  not  the  " button"  or  the  exterior 
u  deflector"  as  have  the  English  lamps.  Mineral-oil  was 
shortly  to  be  introduced  into  this  light-house. 
Meteorological  In  tlie  watch-rooiu  1  observed  a  barometer,  and  outside 

observations.  the  watch-room  window  were  wet  and  dry  bulb  thermome- 
ters. The  principal  keeper  received  200  francs  per  annum 
for  his  meteorological  observations.  A  small  detached  es- 
tablishment contained  a  variety  of  meteorological  instru- 
ments, consisting  of  different  kinds  of  rain-gauges  and  self- 
registering  wind-gauges.  The  extensive  grounds  about  the 
light  house  are  ornamented  with  handsome  flower-gardens 
and  shrubbery,  and  are  inclosed  with  live  hedges. 
at  At  eacb  light-house  are  kept  a  Visitors'  Book,  in  which  are 
recorded  the  names  of  all  visitors ;  a  Service-Book,  in  which 
the  details  of  the  daily  service  of  the  light  (such  as  the  con- 
sumption of  oil,  the  visibility  of  other  lights  within  range, 
&c.)  are  kept ;  and  an  Engineer's  Book,  in  which  are  record- 
ed the  notes  of  inspection  of  the  superintending  or  district 
engineer. 

The  service-lamps,  three  of  which  are  always  on  hand,  are 
required  to  be  changed  every  two  weeks,  the  one  that  has 
just  been  in  use  being  taken  entirely  apart  and  thoroughly 
cleaned  before  it  is  again  used. 

PHATCES  DE  LA  HEVE. 

From  Honfleur,  I  crossed  the  mouth  of  the  Seine  in  a 
steamer  to  Havre.  When  I  left  Paris  I  did  not  intend  to 
go  farther  than  Honfleur,  and  my  letters  from  M.  Allard 
were  only  to  the  engineers  of  the  Corps  des  Fonts  et  Gliaus- 
sees  at  that  place  and  at  Eouen,  but  at  Honfleur  M.  Arnoux 
kindly  gave  me  a  letter  to  M.  Quinette  de  Kochemout,  the 
engineer  charged  with  the  administration  of  the  public 
works,  including  the  lights,  on  the  right  bank  of  the  Seine, 
.  whose  office  is  at  Havre. 

Unfortunately  I  did  not  find  M.  de  Eocheniont  at  home, 
and  I  took  a  carriage  and  proceeded  to  Sainte  Adresse,  near 
Electric  lights,  which  place,  and  on  Cape  la  Heve  are  the  celebrated  double 
electric  lights,  established  respectively  in  1863  and  1865, 
being  the  first  of  that  kind  in  the  world. 

I  arrived  at  the  lights  after  dark,  and  requested  the 
maitre  de pliare  to  show  me  the  establishment,  saying  that 
I  had  endeavored  to  find  M.  de  Eochemont,  but  without 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  221 

success,  showing  him  at  the  same  time  the  letter  addressed 

to  that  gentleman  bv  M.  Arnoux.     He  would  not.  however.  Refusal   of 

7  keeper  to  admit 

read  the  letter,  and  politely  stated  that  he  must  refuse  to  victors  after 
show  me  the  lights,  as  he  had  positive  instructions  not  to 
admit  any  visitors  within  the  station  after  lighting.  He 
was  inexorable  to  all  my  arguments,  and  I  was  at  length 
obliged  to  yield,  and,  while  praising  him  for  his  strict  obedi- 
ence to  orders,  could  not  but  regret  my  unsuccessful  journey, 
and  drive  of  two  leagues  back  to  Havre  in  the  rain  at  mid- 
night, without  seeing  the  interesting  objects  of  my  visit.  I 
mention  this  circumstance  as  indicative  of  the  character  of 
the  French  light- house  keepers  as  far  as  I  saw  them. 

At  all  the  stations  I  visited  I  found  them  to  be  bright, 
intelligent,  and  fond  of  their  profession. 

The  following  morning  I  again  proceeded  to  Cape  la 
Heve,  and  had  the  gratification  of  inspecting  what  is  prob- 
ably the  most  extensive  light-house  station  in  the  world. 
The  towers  are  very  handsome,  and  are  65  feet  high,  their    Focal  planes, 
focal  plane  being  397  feet  above  the  sea. 

The  dwellings,  engine  and  machine  rooms,  &c.,  occupy 
the  intervening  space,  about  300  feet,  between  the  towers. 

In  the  engine-room,  which  is  kept  with  the  utmost  neat-    Boilers. 
ness,  are  two  boilers,  which  are  a  combination  of  the  up- 
right and  horizontal,  and  of  about  eight  horse-power. 

In  the  machine-room  are  four  magneto-electric  machines    Magneto  -  eiec- 
made  by  the  Compagnie  V Alliance  of  Paris.     One  machine/"0  machines- 
running  with  a  velocity  of  four  hundred  revolutions  a  min- 
ute, supplies  each  light ;  and  in  case  of  fog  or  thick  weather 
the  other  machines  are  added,  so  that  the  uncondensed 
beam,  which  in  the  former  case  is  equal  to  200  Carcel-buru-    power  of  un- 
ers,  (2,000  caudles,)  is  increased  400  Carcel -burners,  or  4,000 condei 
candles. 

The  lanterns  which  surmounted  the  towers  when  oil  was    Magneto  -  eiec- 
used  as  the  illuminant  have  been  removed,  and  the  magneto-  S  h? 
electric  lights  are  exhibited  from  what  were  the  watch- watch"rooms- 
rooms.   Small  cylindrical  lanterns,  about  2  J  feet  in  diameter,    Lanterns. 
formed  of  glass,  cast  specially  for  this  purpose,  without  any 
sash-bars,  either  vertical  or  inclined,  being  projected  from 
the  square  seaward  angles,  and  illuminating  about  275°  of 
the  horizon. 

Figs.  25  and  26*  represent  in  plan  and  elevation  the 
electric  light-room,  which  is  in  two  stories,  each  containing 
an  entire  set  of  apparatus. 

*  Figures  25,  26,  and  27  have  been  taken  from  M.  Reynaud's  Mtimoire 
sur  VEclairage  des  Cotes  de  France. 


222  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

In  Fig.  25  A  is  the  lower  room  ;  B.  the  stairway  of  the 
tower  $  C,  steps  leading  to  the  upper  chamber;  D,  door 
leading  to  the  outside  platform ;  K  K,  iron  rails  for  the 
regulators  ;  L,  the  lantern  ;  O,  the  illuminating  apparatus; 
B,  the  spare  regulator ;  S,  the  luminous  beam  of  rays 
emanating  from  a  small  lens  placed  in  rear  of  the  focus,  and 
which  throws  upon  the  wall  an  image  of  the  light.  The 
Fig.  25. 


Plan   of  lantern  and  watch -room,  La  H5ve. 

position  of  this  image,  with  reference  to  a  fixed  mark,  indi- 
cates to  the  keeper  whether  the  light  is  in  the  focus  of  the 
lens,  and  is  of  the  greatest  assistance  to  him,  as  it  is  impos- 
sible to  look  at  the  light  itsejf  without  injury  to  the  eye,  on 
account  of  its  dazzling  intensity.  T  T  are  the  conducting 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

wires  ;  U,  the  switch  for  changing  the  direction  of  the  cur- 
rent ;  V,  an  india-rubber  speaking-tube.  The  arc  of  visi- 
bility of  the  light  is  represented  by  the  arc  m,  n,  p. 

In  Fig.  26  A  A  represents  the  illuminating  apparatus;  B 
B,  rails  for  the  lamps  or  regulators ;  CO,  the  conducting- wires; 
D  D,  the  switches,  and  E  E,  india-rubber  speaking-tube. 

Fig.  26. 


223 


Section  of  lantern  and  watch-room,  La  Heve. 

Iii  each  of  the  lanterns,  two  at  each  tower,  is  placed  a 
fixed  lens  three-tenths  of  a  meter  in  diameter,  the  size  of 
the  sixth  order,  shown  in  Fig.  27,  and  for  each  lens  there  is 
a  duplicate  electric  lamp,  so  that,  in  effect  there  are  three 
reserves  in  case  of  accident. 

It  is  found  by  experience,  however,  as  I  was  informed  by 
the  maitre  de  pliare,  that  a  second  lamp  is  only  required 


224 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


\vlien  changing  the  charcoal  pencils,  so  that  so  many  re- 
serves of  lamps  are  more  than  are  actually  necessary e 


Fie.  27. 


Apparatus 
tin  plicate. 


Optical  apparatus,  La  Heve. 

in  All  the  other  parts  of  the  apparatus,  including  the  en- 
gines, boilers,  and  machines,  are  in  duplicate,  excepting  the 
cables  or  wires  connecting  the  magneto-electric  machines 
with  the  lamps.  These,  M.  Beynaud  afterward  informed 
me  at  Paris,  it  was  not  thought  necessary  to  duplicate,  but 
I  should  infer  that  it  would  be  well  to  provide  in  all  cases  a 
second  wire,  from  the  fact  that  in  observing  the  lights  from 
the  steamer,  while  crossing  the  Seine  from  Honfleur  to  Havre, 
I  saw  that  one  of  them  waxed  and  waned  very  perceptibly, 
and  on  my  questioning  the  maUre  dephare  in  regard  to  it, 
he  stated  that  the  wire  leading  to  that  light  was  in  an  imper- 
fect condition. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  225 

In  regard  to  the  carbons,  I  was  told  that  those  used  for   carbousuBedin 
fog  are  much  larger  than  those  used  in  clear  weather,  in  °' 
order  to  provide  for  the  rapid  consumption  when  two  mag- 
neto-electric machines  supply  each  of  the  lights;  also  that 
the  carbons  now  obtained  in  France  are  much  superior  to    French  carbons 

,.„,.,  -,.-,  \      ,    -r        i-r\  -i-  superior   to    the 

the  English,  (which  were  used  at  La  Heve  during  the  war  English. 
with  Germany,)  and  that  with  the  former  the  impurities 
(which  are  said  to  be  the  only  source  of  danger  to  this 
light)  are  never  so  great  as  to  cause  its  extinguishment, 
and  they  are  also  not  subject  to  the  production  of  that  fine 
black  dust  which  I  observed  at  South  Foreland  and  Souter 
Point  as  in  a  slight  degree  interfering  with  the  full  power 
of  the  dioptric  apparatus. 
I  twill  be  observed  that  the  only  provision  at  La  Heve,  for    Provision  foi 

accidents. 

the  exhibition  of  an  oil-light  in  case  of  accident  from  any 
cause  to  the  supply  of  the  electric  current  to  the  lamp,  is  an 
oil-lamp  in  the  small  lens  used  for  the  electric  light,  pro- 
ducing an  illumination  of  but  little  value  for  sea-coast 
lights  of  their  importance. 
I  was  informed  that  at  Grisuez,  on  the  Straits  of  Dover,  ^ight  at  cape 


where  the  French  government  has  established  another  elec-  Grisnez 

trie  light,  the  old  lantern  and  lens  for  the  use  of  an  oil-lamp 

have  been   retained,  the  electric  light  is  exhibited  from 

the  watch-room,  as  at  La  Heve,  and  an  oil-lamp  is  always 

ready  for  lighting  in  the  first-order  lens  in  Hie  main  lantern. 

A  casualty,  such  as  I  have  mentioned,  requiring  the  substi-    LOSS  of  light  in- 

tuition of  an  oil-lamp  for  the  electric  lamp  at  Grisnez  would  us 

reduce  the  intensity  of  the  light  to  6,300  candles,  while  at 

La  Heve  it  would  be  reduced  from  50,000  to  260  candles  in 

fair  weather,  (and  from  100,000  to  260  candles  in  fog,)  and 

probably  even  less,  as  the  lens  used  for  electric  light  is  not 

suited  in  any  case  for  the  exhibition  of  an  oil-light. 

Drawings  illustrating  the  arrangement  at  Grisnez  were 
kindly  furnished  me  by  Chief  Engineer  Allard,  and  are  re- 
produced in  Plate  XLVI. 

Neither  the  electric  light  at  La  Heve,  nor  those  of  Souter 
Point  or  South  Foreland,  which  I  saw  in  England,  are  suffi- 
ciently high  to  make  necessary  the  plan  which  I  am  informed 
by  General  Sherman  has  been  adopted  at  the  new  electric  Electric  light 
light-house  at  Port  Said,  at  the  Mediterranean  entrance  to 
the  Suez  Canal,  that  of  providing  for  the  tower  an  elevator 
or  "  lift  "  which  is  operated  by  the  steam-power  used  to 
drive  the  magneto-electric  machines. 

Up  to  the  present  time^there  have  been  established  nine 
electric  light-houses,  viz  : 
S.  Ex.  54  -  15 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

In  France,  two  fixed  lights  at  La  Heve,  and  a  revolving 
light  at  Grisnez; 

In  England,  a  fixed  light  at  Dungeuess,  two  fixed  lights  at 
South  Foreland,  and  a  revolving  light  at  Souter  Point ; 

In  Egypt,  a  revolving  light  at  Port  Said  ; 

In  Bussia,  a  fixed  light  at  Odessa. 

The  following  excellent  paper,  which  I  have  found  in  the 
Annales  des  Pont  set  Chaussees,  givesa  clear  exposition  of  the 
electric  sea-coast  lights  at  La  Heve. 

[Translation.] 
DESCRIPTION  OF  THE  ELECTRIC  LIGHT-HOUSES  AT  LA  HEVE 

BY  M.   QUINETTE  DE  ROCHEMONT, 

Engineer  des  Fonts  et  Chaussees. 

Dates  of  con-  The  light-houses  of  La  Heve,  constructed  during  the  lat 
rfgSftogf  andter  part  of  last  century,  were  lighted  for  the  first  time  in 
1774;  wood-fires  were  then  used.  In  1810,  lamps  with  re- 
flectors were  introduced,  which,  in  1845,  were  replaced  by 
dioptric  apparatus.  A  final  change  has  been  recently  effected 
by  the  introduction  of  the  electric  light. 

The  application  of  the  electric  light  to  light-houses  had 

Use  of  electric    , 

piles.  already  been  an  object  of  investigation  for  a  long  time. 

Currents  produced  by  electric  piles  were  first  tried,  but  their 
intensity  very  rapidly  decreased  when  the  apparatus  had 
been  in  operation  for  some  time ;  the  expense  was  consid- 
erable, and,  besides,  it  appeared  rather  hazardous  to  confide 
to  ordinary  keepers  the  care  of  keeping  and  regulating  the 
piles.  The  system  based  on  induction  currents  gave,  on  the 
contrary,  very  good  results,  in  experiments  made  at  tbe  Cen- 
tral Light-House  Workshops  at  Paris ;  so  that  in  1863  the 
Test  of  electric  Minister  of  Public  Works  decided  that  one  of  thelight-houses 

2?ilH^e.madeofLaBeve  should  be  iUuminated  provisionally  by  electric 
light  as  a  test.    As  the  experiment  confirmed  the  anticipa- 
tions, electric  illumination  was  definitively  applied  to  both 
light-houses  toward  the  end  of  1865. 
Descr-  tion  of     ^ne  currents  are  produced  by  magneto-electric  machines 

the  apparatus,  worked  by  steam-engines,  and  are  carried  by  conducting- 
cables  to  the  regulators,  or  electric  lamps,  used  to  regulate 
the  separatior  of  the  carbon  points,  between  which  the  light 
is  produced.  The  magneto-electric  machines  and  the  en- 
gines are  placed  in  the  center  of  the  keepers'  dwelling,  in 
two  rooms  fitted  up  for  that  purpose.  (See  Plates  XXXVII, 
XXXVIII,  and  XXXIX.) 


nX 
ro 
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I 


^y 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  227 

The  steam-engines  are  two  iu  number,  and  present  no  pe-  steam  engines. 
culiarity  worthy  of  notice,  as  they  belong  to  the  common 
stationary  class  with  locomotive-boiler  of  eight  horse-po^er. 
They  are  certified  as  capable  of  resisting  a  pressure  of  70 
pounds  to  the  square  inch.  But  one  engine  is  generally 
used  at  a  time,  as  it  is  sufficient  to  work  two  magneto-elec- 
tric machines.  At  first  it  was  thought  necessary  to  keep 
the  second  engine  with  banked  fires  in  case  of  accident  to 
the  first,  but  practice  has  shown  that  this  precaution  was 
needless.  The  motion  is  conveyed  from  the  steam-engines 
to  the  machines  by  belts  and  an  intermediate  shaft.  (Plates 
XXXVIII  and  XXXIX.) 

The  magneto-electric  machines  were  furnished  by  the  Al-  tri^5faDc^,eslec" 
liance  Company.  They  are  composed  (Plates  XL,  XLI,  and 
XLII)  of  a  cast-iron  frame  on  which  are  placed  mahogany 
cross-pieces  which  serve  as  supports  to  seven  parallel  series 
of  compound  magnets,  all  of  which  converge  toward  the 
central  axis  of  the  frame.  The  magnets  of  the  two  outer 
series  are  formed  of  three  superposed  plates,  curved  horse- 
shoe shape,  the  others  of  six  plates.  They  are  so  arranged 
that  the  poles  nearest  each  other,  both  horizontally  and  ver- 
tically, are  always  of  opposite  signs.  The  six- plate  magnets 
are  of  a  power  of  145  to  155  pounds,  the  three-plate,  about 
75  pounds.  Between  the  seven  rows  of  magnets,  there  re- 
volve six  bronze  disks,  (Plate  XLIII,Figs.  1  and  2,)  mounted 
on  an  axis  supported  by  the  frame.  On  each  of  these  disks, 
sixteen  induction-spools  are  fixed  by  bronze  clamps  and 
screws.  (Plate  XLIII,  Figs.  10  and  15.)  Each  spool  (Plate 
XLIII,  Figs.  10-14)  is  a  tube  of  soft  iron  about  one- third  of 
an  inch  thick,  1J  inches  in  exterior  diameter,  and  3f  inches 
long,  slit  radially  so  as  to  more  quickly  lose  its  magnetism. 
Each  tube  is  wound  with  eight  copper  wires  one- twenty-fifth 
of  an  inch  in  diameter  and  about  50  feet  long,  so  that  there 
are  about  400  feet  of  wire  wound  around  the  spool.  These 
wires  are  covered  with  cotton  and  insulated  by  asphalt  dis- 
solved iu  spirits  of  turpentine ;  they  are  wound  in  the  same 
direction  on  all  the  spools. 

The  best  method  of  placing  the  spools  has  been  deter-    Method 'of 

placing    the 

mined  by  experiment  and  trial ;  a  certain  number  of  ex-  spools, 
tremities  of  wires  of  the  same  sign  or  denomination  are 
brought  together,  and  an  equal  number  of  extremities  of  the 
opposite  sign.  All  the  extremities  of  one  sign  communicate 
with  the  central  axis  of  the  machine,  all  of  the  other  sign 
with  a  metallic  sleeve  fixed  on  the  axis  but  insulated  from 
it  by  a  plate  of  India  rubber  placed  concentrically  and  joined 
to  two  other  perpendicular  plates.  (Plate  XLIII,  Figs.  5-8.) 


228  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

The  shaft  and  sleeve  revolve  in  journal-boxes  (Plate'  XLIII, 
Figs.  5,  6,  9)  insulated  from  the  rest  of  the  frame  by  plates 
of  vulcanized  rubber.  From  these  boxes  and  the  axis  start 
the  wires  which  transmit  the  currents  generated  by  the  ma- 
chine. 

induction  -cor-  Induction-currents  are  produced  whenever  the  spools 
either  approach  or  leave  the  poles  of  the  magnets.  Thus 
there  are  sixteen  changes  of  direction  of  the  current  to  each 
revolution  of  the  cylinder  ;  and  the  wires  are  therefore  alter- 
nately traversed  by  currents  of  opposite  direction  and  a 
series  of  discontinuous  sparks  is  obtained.  The  eye,  how- 
ever, perceives  no  interval,  for  the  number  of  sparks  ex- 
ceeds 100  per  second,  since  the  magneto-electric  machines 
make  from  390  to  400  revolutions  per  minute. 

Gron.pingof  Four  magneto-electric  machines  (Plates  XXXVIII, 
XXXIX,  XL,  XLI,  XLII)  have  been  set  up.  They  are 
grouped  two  and  two,  each  group  connected  with  one  of  the 
lights.  Under  ordinary  circumstances  one  steam-engine 
works  two  machines,  one  of  each  group,  but  during  a  fog, 
when  it  is  wished  to  increase  the  intensity  of  the  lights, 
each  group  of  machines  is  worked  by  an  engine.  For  this 
purpose  the  shaft  for  transmitting  the  motion  is  of  two 
parts,  which  are  connected  or  disconnected  at  pleasure,  as 
either  ordinary  or  double  light  is  wished,  (Plate  XLII,  and 
Plate  XLIII,  Figs.  3,  4,  and  16.)  In  the  latter  case  the  two 
machines  of  the  same  group  are  connected. 

switches.  Accordiugas  it  is  wished  to  use  one,  the  other,  or  both  oi 

the  machines  connected  with  one  light-house,  it  is  necessary 
to  change  the  points  of  attachment  of  the  conducting-  wires. 
In  order  to  avoid  the  mistakes  which  might  result,  M.  Joseph 
Yan  Malderen,  superintending  engineer  of  the  Alliance 
Company,  has  contrived  a  most  ingenious  switch,  placed  in 
the  machine-room,  (Plate  XLIY,  Figs.  1  to  4.)  I*rom 
this  switch  alone  proceeds  the  cable  conducting  the  electric 
currents.  This  cable  is  composed  of  three  wires,  one  of 
which,  /?,  communicates  directly  with  the  wire  b,  uniting 
the  axes  of  one  of  the  groups  of  machines,  while  the  two 
others,  a  and  ^,  proceed  from  buttons  at  the  lower  part  of 
the  switch.  The  wires  a  and  c,  coming  from  the  journal- 
boxes  of  the  machines,  are  brought  to  two  buttons  at  the 
upper  part  of  the  switch. 

The  communication  between  vthe  wires  a  or  c  (Plate  XLIY, 


between    the-,.        _.  ,  .    ,          i  TIJP         -i  • 

wires.  Fig.  3)  and  the  wire  «,  which,  when  a  light  of  ordinary  in- 

tensity is  required,  is  always  the  one  which  conducts  the 
current  to  the  lights,  is  through  a  forked  piece  of  metal,  one 
end  of  which  is  attached  by  a  pin  to  the  upper  button  which 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  229 

corresponds  to  the  machine  then  in  operation.  On  the  con- 
trary, when  a  light  of  double  intensity  is  wished,  the  cur- 
rents arriving  at  the  upper  buttons  pass  to  the  wires  a  and 
Y  through  two  straight  rods,  (Plate  XLIY,  Fig.  1,)  and  do 
not  meet  until  they  reach  the  interior  of  the  lamp.  Thus 
no  displacement  of  the  wires  need  be  feared,  as  all  are 
permanently  attached  to  the  machines  or  switches,  the 
switch-key  being  all  that  it  is  necessary  to  touch.  Each 
cable  is  carried  underground  to  the  light-house,  thence 
through  the  stairway  to  the  lantern. 

In  order  to  avoid  extinctions  which  might  result  from  ac-    Duplicate   op- 
cidents  to  the  regulators,  it  has  been  thought  necessary  totic 
have  in  each  light-house  two  optical  apparatus,  one  above 
the  other,  and  for  each  two  lamps.    These  lamps  slide  on 
rails  fastened  to  a  cast-iron  plate,  and  can  thusbe  movedinto 
exact  position. 

As  it  was  also  wished  to  avoid  displacing  the  conducting    second  switch. 
wires  in  the  light-house  lanterns,  a  second  switch  is  used, 
by  which  the  light  can  be  doubled  on  either  stage  at  will 
without  moving  the  wires.     (Plate  XLIV ,  Figs.  5  and  6.) 

The  wire  /9,  corning  from  the  axes  of  the  two  machines  of 
the  same  group,  connects  directly  with  the  lower  cast-iron 
table,  and  the  communication  between  the  two  tables  is 
through  one  of  the  uprights  of  the  lantern,  also  of  cast 
iron.  The  current  passes  directly  from  the  table  into  the 
lamp  to  reach  the  upper  carbon  point,  as  will  be  seen  here- 
after. The  wire  «  communicates  with  a  large  copper  bolt, 
A,  (Plate  XLIV,  Figs,  o  and  6)  by  the  metallic  plate  on 
which  the  bolt  slides.  The  wire  Y  communicates  in  the  same 
way  with  another  bolt,  B,  sliding  vertically  like  the  large 
one,  from  which,  moreover,  it  is  magnetically  insulated  by 
an  ivory  handle. 

When  the  bolts  are  pushed  down,  the  currents  arrive  by 
the  wires  «  and  y,  pass  into  the  wires  a1  and  •/,  and  go  to  the 
lower  stage ;  on  the  contrary,  if  the  bolts  are  pushed  up,  the 
currents  pass  into  the  wires  a"  and  /',  and  thus  reach  the 
upper  stage.  If  the  light  is  of  ordinary  intensity,  there  is 
no  current  in  the  wire  ^,  and  consequently  none  in  the  wires 
Y1  and  Y"-  The  currents  from  the  wires  a1  or  a"  reach  the 
lamp  through  a  flat  metallic  spring  placed  above  the  cast- 
iron  plate  on  which  the  lamp  rests.  In  case  of  double  light 
the  currents  from  the  wires  Y'  or  Y"  reach  the  interior  of  the 
lamp  by  a  second  spring  placed  at  the  side  of  the  first. 

In  this  way,  when  double  light  is  used,  only  one  of  the  use  of  siugie 
stages  of  the  lantern  is  lighted.  Experience  has  shown  that  doifbfe6  light  °is 
it  is  better  to  give  double  light  on  one  stage  than  ordinary  n£ 


230  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

light  on  both,  though  at  little  distance  the  two  lights  (sepa- 
rated about  7  feet)  appear  as  one. 
Lamps,  or  eiec-  -  Serrin's  regulators,  the  only  ones  used  at  La  Heve,  (Plate 

trie  rcguuitory.      __.__  __  . 

XL V  )  are  composed  of  two  point-holders,  each  attached 
to  a  vertical  rod  which  slides  in  a  guide- tube.  The  rods  are 
so  arranged  that  when  the  upper  one  descends  by  its  weight 
the  other  rises.  To  effect  this,  the  upper  rod  in  descending 
pulls  the  chain  A,  one  end  of  which  is  attached  to  the  lower 
end  of  the  rod  and  the  other  to  a  pulley,  0.  This  pulley,  in 
turning,  winds  up  another  chain,  B,  attached  to  the  lower 
end  of  the  lower  point-holder.  Thus  both  rods  move  to- 
gether 5  but,  as  it  has  been  found  that  the  lower  carbon 
point  consumes  somewhat  more  rapidly  than  the  other,  the 
pulley  0  has  two  barrels  of  slightly  different  diameter  $  ex- 
perience has  shown  that  they  should  be  to  each  other  as  100 
to  108  to  keep  the  luminous  point  always  at  the  same  height. 
The  motion  of  the  pulley  is  transmitted  by  clock-work  to  the 
fly-wheel  D,  used  to  moderate  the  movement  of  the  point- 
holders  when  they  approach  each  other,  impelled  by  the 
weight  of  the  upper  rod. 

The  lower  guide-tube  is  carried  by  an  oscillating  parallelo- 
gram, MNOP,  affected  by  two  forces  acting  in  opposite 
directions ;  one,  the  tension  of  the  spiral  spring  E,  which 
raises  it ;  the  other,  the  action  of  the  electro-magnets  S,  on 
the  armature  Q  attached  to  the  parallelogram,  which  lowers 
it.  When  the  lamp  is  in  use  and  the  points  are  at  a  proper 
distance  from 'each  other,  the  armature  Q  is  attracted  by 
the  electro-magnets  5  the  parallelogram  descends,  the  pawl 
F,  carried  thereon,  engages  the  ratchet- wheel  E,  mounted  on 
the  same  axis  as  the  fly-wheel  D,  and  the  points  can  no 
longer  approach  each  other.  As  the  points  consume,  their 
separation  increases,  and,  consequently,  the  intensity  of  the 
current  traversing  the  electro-magnets  decreases :  the  arma- 
ture is  attracted  with  less  force,  and  the  parallelogram  re- 
ascends,  the  pawl  F  escapes  from  the  ratchet-wheel,  and  the 
two  points  re-approach,  impelled  by  the  upper  rod.  They 
continue  to  approach  until  the  current  has  resumed  its  nor- 
mal intensity,  when  the  parallelogram  redescends,  attracted 
by  tfre  magnets.  The  points  approach  about  one-twen- 
ty-fifth of  an  inch  every  time  a  tooth  of  the  wheel  escapes 
from  the  pawl. 

By  a  screw,  T,  acting  on  a  lever,  the  tension  of  the  spring 
R  can  be  increased  or  diminished  so  as  to  regulate  the  ac- 
tion of  the  lamp.  This  tension  should,  indeed,  vary  accord- 
ing to  the  intensity  of  the  current  passing  about  the  mag- 
nets S,  as  these  two  forces  should  be  in  equilibrium  when 


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EUROPEAN   LIGHT-HOUSE    SYSTEMS.  231 

the  points  are  a  proper  distance  apart ;  the  voltaic  arc  can 
thus  be  kept  of  a  constant  length. 

As  we  have  already  stated,  the  currents  enter  the  regu-  course  of  the 
lator  by  the  base-plate  and  through  either  one  or  two  springs 
placed  beneath,  as  either  ordinary  or  double  light  is  required- 
In  the  former  case  the  current  passes  from  one  of  the  springs 
into  one  of  two  pieces,  shown  together  at  Y;  thence  around 
the  two  magnets  S,  through  the  piece  XX,  and  reaches  the 
oscillating  tube  and  the  lower  point-holder.  In  the  second 
case,  the  other  current  of  the  same  denomination,  conducted 
by  the  wires  /  or/7,  passes  from  the  second  spring  into  the 
second  piece  at  Y,  and  attains  the  piece  V,  where  it  meets 
the  first  current,  without  having  passed  about  the  electro- 
magnets. The  current  of  the  contrary  sign  passes  from  the 
base-plate  through  all  the  other  parts  of  the  lamp  to  reach 
the  upper  point-holder.  The  parts  traversed  by  currents  of 
contrary  signs  are  insulated  from  each  other  by  vulcanized 
rubber  and  ivory.  To  assure  good  working  of  the  lamp,  M. 
Serrin  has  contrived  some  devices  which  we  will  point  out.  1"  ° 

When  the  upper  rod  is  raised,  the  pulley  C  (on  which  are 
wound  the  chains  connecting  the  ends  of  the  rod)  revolves; 
but,  to  prevent  forcing  the  clock-work,  a  ratchet-wheel,  G, 
is  placed  on  the  same  axis  as  the  first  cog-wheel. 

The  two  screws  H  and  I,  which  meet  two  pieces  on  the 
side  NO  of  the  parallelogram,  limit  its  motion. 

By  the  screw  K  (Plate  XLV,  Fig.  1)  the  upper  rod  can  be 
raised  or  lowered  to  alter  the  position  of  the  luminous 
point.  In  his  last  lamps  M.  Serrin  has  adopted  a  much 
better  device,  by  which  the  luminous  point  can  be  placed  in 
exact  position  by  moving  both  carbons  at  once,  thus  prevent- 
ing any  decrease  of  light.  For  this  purpose  the  chains  A  and 
B  are  run  over  a  little  auxiliary  pulley  which  can  be  moved 
up  or  down  by  a  screw  and  lever  so  as  to  raise  or  lower  both 
points  the  same  distance  at  the  same  time.  This  device  is 
applied  to  four  of  the  lamps  in  use  at  La  Heve. 

A  small  gauge,  Z,  movable  around  the  upper  rod,  indicates 
the  exact  height  at  which  to  place  the  gap  between  the  car- 
bons; that  is  to  say,  the  luminous  point.  By  the  two  screws 
L  and  I/  the  carbon-points  can  be  adjusted  exactly  opposite 
each  other  by  moving  the  upper  point  in  a  direction  either 
parallel  or  perpendicular  to  the  plane  of  the  two  rods. 

Finally,  to  prevent  the  point-holders  burning  when  the 
carbon  is  consumed  they  stop  at  a  distance  of  about  2J  inches 
from  each  other,  as  then  the  upper  rod  strikes  the  base  of 
the  lamp  and  can  go  no  farther. 


232  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Another  regulator,  invented  by  M.  Foucault  and  con 


structed  by  M.  Dubosq,  has  also  been  tried.  It  was,  how- 
ever, not  well  adapted  to  be  placed  on  a  cast-iron  table,  and 
was  twice  broken  within  a  short  time,  in  consequence  of  a 
too  great  separation  of  the  carbon  points.*  Its  use  was 
then  abandoned. 

carbon  points.  The  carbon  points  used  for  electric  illumination  are  man- 
ufactured from  the  residue  contained  in  gas-retorts.  They 
are  about  10  inches  long  and  from  one-third  to  one-half  an 
inch  thick,  according  as  they  are  used  for  ordinary  or  double 
light. 

optical  appa-  The  optical  apparatus,  Fig.  27,  are  about  one  foot  in 
diameter  $  the  catadioptric  rings  are  symmetrical,  both 
above  and  below,  on  account  of  the  form  of  the  points  and 
fhe  luminous  center.  The  luminous  rays  are  sent  from  the 
rings  tangentially  to  the  surface  of  the  sea.  The  joints  of 
the  rings  are  placed  in  a  direction  parallel  to  that  taki  n  by 
the  rays  after  their  refraction.  The  luminous  center  being 
of  very  small  dimensions,  (about  two-fifths  of  an  inch  by 
two-fifths  to  three-fifths  of  an  inch,)  the  lantern  can  have 
no  sash-bars,  as  the  occupation  of  a  part  of  the  horizon. 
which  they  would  produce  must  be  avoided. 

Tll°  divergence  of  the  luminous  rays  is  about  6°;  about 
^6    same  as  tbat  of  a  first-order  oil-light,     It  is  indis- 
.oint,  pensable  that   the  luminous  point  should  remain  in   ex- 

actly the  proper  position  in  the  optical  apparatus,  as  a 
vertical  displacement  of  one-fifth  of  an  inch  would  raise  or 
lower  the  luminous  beam  2°.  To  assure  a  correct  position 
for  the  luminous  center,  there  has  been  attached  to  the 
edge  of  the  optical  apparatus  a  small  lens,  which  throws 
the  image  of  the  points  on  a  screen  placed  at  the  other  end 
of  the  service-room.  This  image  should  be  in  such  a  posi- 
tion that  the  gap  between  the  points  appears  on  a  line  pre- 
viously traced  on  the  screen.  If  it  does  not,  the  position 
of  the  luminous  center  should  be  adjusted  as  has  been  indi- 
cated above.  The  image  is  magnified  22  diameters. 

The  lights  of  La  Heve  illuminate  three-fourths  of  the 
horizon.  The  lanterns  and  service-rooms  are  at  the  un- 
lighted  angle. 

other  aids.          Oil-lam  ps  with  large  burners  can  be  placed  in  the  center 

of  the  optical  apparatus  if  there  should  occur  an  accident 

_  preventing  the  production  of  electric  light  ;  in  such  case  one 

of  these  burners  is  placed  on  each  stage  of  the  lantern. 

M.  Dubosq  has  since  placed  a  ^top-piece  to  prevent  the  too  great  sepa- 
ration of  the  points;  the  lamp  works  with  more  regularity,  but  we 
have  not  again  used  it. 


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EUROPEAN    LIGHT-HOUSE    SYSTEMS.  233 

Each  luminous  point  has  about  \the  intensity  of  a  fourth - 
order  light  $  at  a  short  distance  the  two  lights  blend  and 
appear  as  one. 

Call-bells  with  dials  connect  the  engine-room  and  the    caii-beiis. 
light-house  lanterns,  so  that  the  engineers  and  keepers  can 
communicate  with  each  other.    Other  bells  are  placed  in 
the  dwellings  of  the  principal  and  other  keepers. 

Water  for  the  steam-engines  and  for  domestic  use  is  kept  water. 
in  cisterns  of  a  total  capacity  of  about  46,000  gallons.  It 
is  rain-water  collected  from  the  roofs  of  the  buildings  and 
from  courts  paved  with  asphalt,  a  total  surface  of  about 
2,000  square  yards.  It  is  pumped  by  the  engines  into  a 
tank  near  the  engine-room,  (Plate  XXXVIII.)  There  is  a 
small  workshop,  so  that  the  engineers  can  make  all  current 
repairs  which  do  not  require  special  artisans  or  implements. 

In  charge  of  the  lights  there  is  a  principal  keeper,  (mditre  organization  of 
dephare,)  who  has  under  his  orders  six  assistants,  (gardiens,) the  servicc- 
two  of  whom  are  engineers,  whose  special  duty  is  to  attend 
to  the  steam-engines j  the  others  attend  the  lamps.  The 
engineers  have  the  title  and  rank  of  keepers  (gardiens)  of 
the  first  class,  but  as  their  service  is  much  more  arduous 
than  that  of  their  comrades,  an  extra  compensation  is 
allowed  them  at  the  end  of  the  year  if  they  have  given  sat- 
isfaction. With  a  view  to  subordination  and  harmony  of 
relations  at  the  lights,  it  seemed  better  to  give  these  em- 
ployes a  relative  rank  rather  than  to  exclude  them  from  the 
service  by  giving  them  the  title  of  engineers. 

Since  commencing  the  use  of  electricity  (November  1,    Accitloilts 
1805)  several  accidents  and  a  few  extinctions  have  occurred, 
We  give  below  a  complete  list. 

March  o,  1866. — The  suspension-chain  of  the  upper  rod  of 
one  of  the  electric  regulators  breaks. 

A2)ril  8. — Light  out  five  to  six  minutes,  in  consequence  of 
the  slipping  off  of  several  of  the  belts. 

July  12. — The  heel-screw  of  one  of  the  magnets  of  ma- 
chine No.  22  becoming  loose,  rubs  against  the  spools  of  one 
series  and  injures  them  so  that  several  have  to  be  replaced. 
As  this  accident  happened  at  the  moment  of  setting  the 
machine  in  motion,  no  extinction  resulted. 

July  27,  September  5,  September  8,  September  12. — The  sus- 
pension-chains of  the  upper  rod  of  four  regulators  break ; 
the  damaged  lamp  being  immediately  replaced  by  another, 
the  light  was  out  but  a  few  seconds. 

October  2. — Four  mahogany  cross-pieces  of  machine  No. 
19  are  broken ;  four  spools  are  injured.  The  reserve  machine 


234  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

being  immediately  set  in  motion,  tbe  light  was  out  bat  a 
short  time. 

January  11,  1867. — The  suspension-chain  of  the  lower  rod 
of  a  regulator  breaks. 

March  9. — Light  out  3  minutes,  the  belt  of  the  engine 
having  slipped  off. 

March  17. — Light  out  3  minutes,  the  fire-grates  of  the  en- 
gine having  fallen. 

March  25. — Southern  light  out  7  minutes  and  3  minutes. 

March  29  to  30. — At  10.35  p.  m.  the  southern  light  out, 
Being  unable  to  relight  it,  oil-lamps  are  placed  in  the  lens- 
apparatus.  At  2.35  a.  m.,  on  again  trying  the  electric  light, 
it  works.  Electric  light  out  about  4  hours. 

May  25. — At  12.5  a.  m.  the  water-pipe  of  the  engine  bursts, 
the  pressure  falls;  reflectors  are  lighted  at  12.20.  The  dam- 
age having  been  repaired,  the  electric  light  is  re- established 
at  1.5. 

November  20. — Southern  light  out  5  minutes,  caused  by 
the  slipping  off  of  the  belt  of  the  magneto-electric  machine. 

January  5,  18G8. — Southern  light  out  9  minutes. 

March  3. — Light  out  7  minutes,  caused  by  the  belt  of  the 
steam-engine  having  twice  slipped  off. 

March  19. — Light  out  2  minutes.  The  pin  of  the  fly-wheel 
becoming  loose,  it  was  necessary  to  tighten  it. 

May  4. — Southern  light  out  3  minutes,  the  belt  of  the 
magneto-electric  machine  falling  off  at  the  time  of  firing  up 
the  southern  engine. 

October  26. — At  the  moment  of  lighting,  the  joint  of  the 
steam-gauge  of  the  southern  engine  bursts.  The  fires  of  the 
northern  engine  are  lighted,  but  before  steam  is  up  the  acci- 
dent is  repaired,  so  that  the  hour  of  lighting  is  not  delayed. 

October  30,  1869.— Northern  light  out  15  minutes,  the 
keeper  having  fallen  asleep. 

In  addition  to  the  extinctions  mentioned  above,  which 
were  the  result  of  accidents,  there  occur  every  night  a*few 
others  of  short  duration,  which  cannot  be  avoided.  When 
the  lamps  are  changed,  for  instance,  the  light  is  out  a  few 
seconds ;  also,  when  double  light  is  to  be  produced  after 
ordinary  light,  or  vice  versa,  it  is  necessary  to  throw  in  or 
out  of  gear  the  two  parts  of  the  shaft  connecting  the  two 
magneto-electric  machines  of  the  same  group,  so  the  light 
is  out  2  to  3  minutes. 

rpo  recapitulate,  we  find  that  in  four  years  there  have 
occurred — 


LIGHTHOUSES    OF  LA 

ELECTRIC   LIGHTS. 


MAGNETO-ELECTRIC    MACHINE 

SIDE    ELEVATION. 


PLATE  XLI 


SCALE. 

tJtc/lft  Jj»  V  f  j  Q 7 


TJ1S! 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Three  extinctions  of  2  minutes,  3  minutes,  and  1  hour 
duration,  caused  by  accidents  to  the  steam-engine. 

Five  extinctions  of  from  3  to  7  minutes,  caused  by  the 
slipping  off  of  the  belts.  These  extinctions  were  the  result 
of  the  negligence  of  the  keepers.  Measures  have  been  taken 
to  prevent  similar  occurrences. 

Two  accidents  to  the  magneto-electric  machines,  from 
which  no  extinctions  of  consequence  resulted,  as  the  machine 
in  reserve  was  immediately  set  in  operation. 

Six  lamps  were  sent  back  to  Paris  in  consequence  of  the 
breaking  of  the  suspension-chain  of  one  of  the  carbon 
holders,  but  the  extinctions  caused  by  these  accidents  are 
not  worthy  of  mention. 

Four  extinctions  of  3,  7,  9  minutes,  and  4  hours'  duration, 
the  causes  of  which  we  have  not  been  able  to  determine. 

One  extinction  of  15  minutes,  resulting  from  the  sleep  of 
a  keeper. 

The  extinctions  originating  from  the  steam-engines,  or 
the  slipping  off  of  belts,  offer  nothing  particularly  worthy 
of  notice ;  one  only  exceeded  7  minutes,  and  was  the  result 
of  the  breaking  of  the  water-pipe ;  the  others  are  mainly 
attributable  to  the  negligence  of  the  machinists. 

The  accidents  which  occurred  to  the  magneto-electric  ma-  causes 
diines  rendered  it  necessary  for  M.  Joseph  Van-Maldereu, 
superintending  engineer  of  the  Alliance  Company,  to  makechiues- 
a  journey  to  Havre,  in  order  to  attend  to  their  reparation. 
The  second  of  these  accidents  was  probably  caused  by  the 
falling  out  of  one  of  the  wedges  used  for  keeping  the  mag- 
nets in  position,  and  the  magnet  having  nothing  to  hold  it, 
hit  the  wheel  carrying  the  spools. 

The  breaking  of  the  suspension-chain  of  one  of  the  carbon-    Cause  of  break- 
holders  (an  accident  which  occurred  six  times)  was  caused  sum-chain  oi>ptie, 
by  these  chains  passing  too  near  other  parts  from  which ca 
they  should  have  been  separated,  and  thus  becoming  heated. 
M.  Serriu  has  easily  succeeded  in  remedying  these  disad- 
vantages, and  they  will  not  again  occur. 

The  extinctions  of  7,  3.  and  9  minutes,  occurring  to  the    Extinctions  b\- 

..  ..    ,  J  ...  unknown  causes. 

southern  light,  are  due  to  causes  which  we  have  been  unable 
to  ascertain  $  it  is  probable  that  they  were  the  consequences 
of  a  lack  of  vigilance  on  the  pact  of  the  keepers.  In  regard 
to  the  extinction  of  four  hours'  duration,  we  are  unable  to 
attribute  its  cause  to  anything  but  malice  on  the  part  of 
some  one,  for  the  light  went  out  at  10.35  p.  m.,  and  it  was 
impossible  to  relight  it,  as  the  currents  no  longer  reached 
the  lantern.  Subsequently,  however,  when  we  arrived, 
about  2  o'clock  a.  m.,  the  light  was  immediately  restored 


236  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

without  anything  being  done  to  the  machines.  The  two 
conducting-wires  had  probably  been  connected  at  some 
point  before  reaching  the  lantern,  and  the  circuit  being 
thus  closed,  the  currents  no  longer  reached  the  lamp.  It 
is  proper,  however,  to  state  that  an  open  investigation  on 
this  subject  gave  no  result. 
Decrease  m  the  The  list  given  above  will  show  that  accidents  happen 

Ss.er  C1"  less  and  less  frequently.  Such  a  result  might  have  been 
foreseen  to  a  certain  extent  ;  still  it  is  well  to  prove  it.  As 
the  keepers  become  better  and  better  acquainted  with  the 
management  of  the  apparatus  of  which  they  have  charge, 
they  become  less  surprised  at  incidents  which  may  occur, 
and  can  immediately  apply  the  proper  remedies  to  a  state 
of  things  which  might  become  grave  if  allowed  to  continue. 
Thus,  one  of  the  engineers,  who  has  been  in  the  light-houses 
since  the  end  of  1863,  has  never  had  any  accidents  on  his 
watch,  while  others  serving  during  the  same  period  have 
had  only  too  many. 
Substitution  oi  In  addition  to  the  accidents  mentioned  above,  it  was 

engines.  found  necessary,  at  the  beginning  of  1868,  to  substitute  new 

steam-engines  for  those  which  had  been  in  the  service  since 
1865,  and  likewise  to  replace  some  of  the  journal  boxes  of 
the  magneto-electric  machines. 


ow  engines  iu-     ^ae  old  steam-engines  were   furnished  by  M.  Bouffet: 

sufficient. 

they  were  of  five  horse-power  and  certified  for  a  pressure  of 
six  atmospheres.  This  was  found  insufficient  for  the  labor 
they  had  to  perform.  From  experiments  made  on  their 
greatest  power,  in  March,  1866,  the  results,  indeed,  showed 
that  they  were  unable  to  develop  continuously  more  than 
six  horse-power  ;  that,  under  these  conditions,  they  gave 
one  hundred  revolutions  per  minute,  and  the  mean  pressure 
in  the  boiler  was  five  and  a  half,  without  ever  reaching  five 
and  three-quarters  atmospheres.  Now,  to  produce  a  light 
of  normal  intensity,  these  engines  are  required  to  make  one 
hundred  revolutions,  and  the  pressure  was  five  and  a  quar- 
ter atmospheres.  The  engines  were  thus  necessarily  driven 
to  the  limit  of  their  capacity,  which  could  not  be  otherwise 
than  very  injurious,  resulting  in  rapid  waste.  Already,  in 
1867,  a  part  of  the  plates  of  the  fire-box,  and  the  pipes  of 
the  southern  engine,  had  to  be  replaced  at  an  expense  of 
$385.25.  Other  repairs  made  on  these  engines  to  prevent 
them  from  heating  cost  $234.60. 

The  magneto-electric  machines  are  furnished  with  the 
self-lubricating  journal-boxes  of  Avisse,  but  in  the  insula- 
ted parts  the  arbors  had  the  same  diameter  beyond  the  jour- 
nal-boxes ;  the  oil  was  drawn  along  by  centrifugal  force,  and 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


237 


the  bearing  was  not  uniformly  lubricated.  On  this  account 
the  journals  did  not  wear  evenly,  which  was  remedied  by 
grooving  the  arbor  beyond  the  box.  The  worn  journals 
had  to  be  re-turned,  and  the  cushions  of  the  journal-box  re- 
newed. 

Quite  a  number  of  different  apparatus  are  combined  to    causes  of  ti><> 

_  .    irregularity      o  t 

produce  the  electric  light;  if  any  are  not  in  proper  condi-  the  light. 
tioii  they  affect  the  light. 

If  there  is  a  lack  of  pressure  in  the  boiler,  the  magneto- 
electric  machines  run  slowly  and  the  light  scintillates  mark- 
edly ;  instead  of  a  steady  light,  the  eye  perceives  successive 
flashes. 

The  bearings  of  the  central  shaft  of  the  machines  must  be 
well  insulated,  as  otherwise  the  light  loses  in  intensity. 

In  the  regulators  the  separation  of  the  carbon  points  some- 
times varies  5  the  light  decreases  until  they  return  to  a 
proper  position.  This  disadvantage  has  been  almost  en- 
tirely obviated  by  recent  modifications  made  by  M.  Serrin. 
By  suitably  regulating  the  tension  of  the  spiral  spring  the 
variations  of  intensity  of  the  light,  as  far  as  depends  on  the 
regulator,  may  be  almost  entirely  prevented. 

.The  principal  causes  of  tlie  irregularity  of  light  originate    want  of  iiomo- 
iu  a  want  of  homogeneity  of  the  carbon  points  and  the  dis- 
placement  of  the  voltaic  arc. 

The  points,  as  we  have  already  stated,  are  made  of  the 
carbon  deposits  of  gas-retorts.  This  is  sufficient  to  explain 
their  want  of  homogeneity.  They  should  be  hard,  well 
pressed,  and  give  a  very  dry  sound  when  broken  ;  by  their 
external  appearance  alone  a  just  estimate  of  their  quality 
can  be  formed.  The  breaking  of  the  points  when  in  use, 
although  rare,  will  sometimes  occur;  this  necessitates  a 
change  of  lamp,  and  therefore  an  extinction  of  a  few  sec- 
onds ;  it  is  not  practicable,  in  fact,  to  wait  until  the  carbon 
points  re-approach,  as  the  luminous  point  would  then  be 
displaced.  The  want  of  homogeneity  of  the  carbon  also 
causes  a  displacement  of  the  luminous  point.  In  order  to 
remedy  this,  M.  Serrin  contrived  the  mechanism  for  simul- 
taneously lowering  and  raising  the  points.  The  metallic  or 
siliceous  grains  found  in  the  substance  of  the  carbons  also 
affect  the  regularity  of  the  light  by  acting  on  the  voltaic 
arc. 

It  is  proper  to  state,  however,  that  these  oscillations  of 
the  light  are  much  stronger  and  more  apparent  when 
near  at  hand  than  when  observed  at  a  distance,  and  that  fcanca 
they  are  no  serious  disadvantage  ;  under  no  circumstances 
could  they  be  confounded  with  those  of  eclipse  or  scintil- 


oscillation   of 


238  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

lating  lights.  These  oscillations,  moreover,  have  greatly 
diminished,  and  electric  lights  may  henceforth  be  consid- 
ered as  quite  steady. 

in-  Experiments  made  at  the  central  light-house  workshop 
show  that  the  mean  intensity  of  the  light  produced  by  a  six- 
disk  magneto-electric  machine  is  two  hundred  burners. 
This  intensity  varies  within  certain  limits,  and  it  was  found 
necessary  to  make  a  great  number  of  experiments  in  order 
to  estimate  its  mean.  The  luminous  center,  placed  in  an 
optical  apparatus  of  one  foot  diameter,  gives  an  intensity 
of  about  five  thousand  burners. 

Expenses  of  the  More  than  four  years  having  elapsed  since  the  definitive 
establishment  of  electric  lights  at  La  Heve,  we  are  enabled 
to  furnish  an  exact  statement  of  the  annual  expenses. 

The  following  table  shows  the  expenses,  including  sala- 
ries. The  items  are  taken  from  the  light-house  journal  and 
from  the  accounts  of  the  conductor: 


o 

X 


m  C 
o  en 


n 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


239 


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240 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


Expense  of  re- 
pairs to  the  ma- 
chinery. 


Expense    for     Rain-water  is  used  for  steam-engines,  but  in  very  dry 

water  for  the  en-  .     ,          r>   -i     -i      -^  •     ±1  i 

years  it  has  failed;  it  is  tkeu  brought  from  Samte-Adresse 
at  au  expense  of  about  40  cents  per  hundred  gallons.  This 
will  explain  the  item  of  expense  for  water  in  1860  and  1868. 

Before  increasing  the  water-collecting  surface,  or  con- 
structing another  cistern,  we  wish  to  ascertain  if  the  saving 
will  justify  the  expense  of  construction. 

The  old  steam-engines  consumed  about  thirty-four  gal- 
lons of  water  per  hour ;  the  new  average  about  forty. 

The  repairs  to  the  machinery  in  1867  and  1868  were  con- 
siderable on  account  of  the  inefficiency  of  the  steam-engines ; 
there  is  every  reason  to  hope  that  this  expense  will  be 
diminished  with  the  new  engines,  which  are  much  more 
powerful ;  we  have  consequently  reduced  this  item  in  the 
last  column.  Other  expenses  for  supplies  and  repairs  in- 
clude stowage  of  coal  and  cleaning  of  cisterns  and  of  the 
water-collecting  surfaces,  washing  of  linen,  and  other  items 
of  little  consequence.  In  order  to  obtain  an  exact  state- 
ment of  the  annual  expense  incurred  for  the  production  of 
electric  light,  it  would  be  necessary  to  add  a  certain  amount 
to  the  figures  mentioned  in  the  preceding  table  for  deterio- 
ration of  the  apparatus.  It  is  proper,  however,  to  state 
that  there  is  but  little  wear  to  most  of  the  machinery.  The 
regulators,  which  have  been  in  use  for  six  years,  work  as 
well  as  on  the  first  day,  the  only  wear  being  to  the  journal- 
item  of  wear  to  boxes  of  the  magneto-electric  machines.  Thus,  the  wear  of 

be  taken  into  ac- 

count.  the  steam-engines  is  almost  the  only  item  to  take  into  ac- 

count.    These  diminish  quite  rapidly  in  value. 

Table  showing  number  of  hours  of  illumination  and  duration  of  the  working 
of  the  engines. 


1866. 

1867. 

1868. 

1869. 

Average 
year. 

ED  fines  workin0"         

H.     M. 

4,  288    55 

H.     M. 
4,  518    33 

H.     M. 

4,  509    47 

H.     M. 

4,496    21 

Hrs. 

4,540 

Magneto-electric  machines 

3  943    25 

4,  152    28 

4,  203    47 

4,188    06 

4,  yno 

Total  hours  illumination.. 

3,872    10 
3  789    55 

4,087    51 
3  989    04 

4,142    47 
4,  129    01 

4,  127     16 

4,087    22 

4,135 
4,  055 

Double  li^ht  used 

82    15 

98    47 

13    46 

39    54 

60 

Time  of  light-     Since  May  1,  1867,  the  time  of  lighting  is  a  quarter  of  an 

ing    and     extiu-  J 

guishing.  hour  after  sunset,  and  the  lights  are  extinguished  a  quarter 

of  an  hour  before  sunrise  ;  while  formerly  they  were  lighted 
a  quarter  of  an  hour  later,  and  put  out  a  quarter  of  an  hour 
earlier;  so  the  total  annual  illumination  is  increased  182£ 
hours.  This  increase  is  taken  into  consideration  in  the  last 
column  of  the  preceding  table.  It  occurred  in  1868,  1869, 
and  a  part  of  1867. 


LIGHTHOUSES  OF  LA  HEVE. 

ELECTRIC   LIGHTS. 

MAGNETO-ELECTRIC   MACHINES 

DETAILS. 


PLATE  XLIII. 


Tig:  15. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  241 

The  steam-engines  are  fired  up  about  an  hour  before  the 
lime  of  lighting.  It  takes  nearly  three-quarters  of  an  hour 
to  get  up  steam. 

The  magneto-electric  machines  are  started  about  ten  min- 
utes before  the  hour  of  lighting,  so  that  the  currents  may 
be  well  established. 

Double  light  is  produced  whenever  the  fog  is  so  dense    Double  light. 
that  keepers  at  La  Heve  cannot  see  the  beacon-lights  on 
the  north  pier  of  Havre. 

Electric  light  was  twice  introduced  at  La  Heve  ;  in  1863    Ex^<;use  ot 
and  18G5.     At  the  first  period  the  superstructure  of  the  tem  of  lighting, 
vsouthern  light-house  was  finally  modified  by  substituting  for 
the  glass  lantern,  mounted  on  a  sub-base,  a  structure  of 
stone-work  with  the  lantern  in  the  angle. 

Temporary  buildings  were  made  for  the  engines,  but  these 
were  demolished  in  1865,  at  which  time  the  lantern  of  the 
northern  light-house  was  also  altered,  and  the  engines  were 
placed  in  the  house  formerly  used  as  a  dwelling  by  the 
principal  keeper,  a  small  building  being  added  in  the  rear. 
Three  new  dwell  ings  for  the  keepers  were  constructed,  as  well 
as  a  cistern,  and  the  water-collecting  surface  was  enlarged. 

Two  sums,  one  of  $6,266.58,  the  other  of  $11,676.50,  were  Expense  of 
expended  for  these  works ;  but  these  do  not  include  the 
price  of  the  steam-engines,  magneto-electric  machines,  regu- 
lators, lanterns,  cupolas,  &c.,  which  were  sent  from  the  cen- 
tral light-house  depot.  As  the  details  of  these  expenses 
have  no  general  interest,  we  shall  not  give  them. 

In  altering  other  light-houses  the  expenses,  taking  into 
account  the  difference  of  location,  would  probably  be  quite 
different. 

We  shall  confine  ourselves  to  giving  some  details  of  prices 

„  ,  Cost  of  special 

ot  special  apparatus,  as  these  prices  are  almost  entirely  in-  apparatus. 
dependent  of  the  situation  of  light-houses  : 
The  two  steam-engines  and  accessories  cost. ...  $2,  493  42 
That  is  to  say, 

Fortwoengines $2,161  60 

Two  Foucault  regulators 77  20 

Two  chimneys 41  56 

Two  bed-plates  for  fly-wheel 56  82 

.     Feed-pipes  and  mounting  of  the  x 

machinery t 156  24 

The  feed-pump  and  water-tank  cost 388  31 

Shaft 378  76 

Six  belts,  about 48  25 

Six  magneto-electric  machines 9,  339  86 

S.  Ex.  54 16 


242  EUROPEAN    LIGHT-HOUSE    SYSTEMS 

Namely,  for — 

Four  machines $9,  264  00 

Columns  and  copper  rods  for  con- 
ductors   56  56 

Two  counters 19  30 

Four  switches,  with  their  accessories $77  07 

Two  eonducting-cables,  about ,. .         271  20 

Eight  regulators,  with  their  accessories 2,  242  66 

Namely,  for — 

Eight  regulators „ .  . .     1,  544  00 

Alteration  of   first  regulator  in 

1865 119  66 

Four  cast-iron  plates,  with  the 

springs '  308  80 

Expenses    for    experiments     al- 
lowed to  M.  Serrin* 270  20 

Four  optical  apparatus 1,  389  60 

Electric  bells 262  50 

comparison  of     From  December  25,  1863,  when  the  southern  light-house 
light!10         n  was  lighted  for  the  first  time  by  electricity,  to  August  31, 
1865,  the  date  when  the  northern  light-house  was  still  light- 
ed with  oil,  it  was  easy  to  compare  the  two  modes  of  pro- 
ducing light.     At  that  time  the  magneto-electric  machines 
had  but  four  disks ;  the  intensity  of  the  luminous  point  was 
only  125  burners,  and  the  intensity  of  the  beam  sent  to  the 
horizon  not  more  than  3,500  burners  when  ordinary  light 
electric  fnminous  was  used.     The  intensity  of  the  oil -lights  was  630  burners. 
light.    an_t  From  information  obtained  in  1865,  it  seems  that  the  elec- 

tric light  always  was  seen  before  the  other,  even  in  clear 
weather,  t  The  light  of  Barfleur  was  often  seen  at  the  same 
Raiige  of  eiec-  time  as  the  electric  light  of  La  Heve.  According  to  state- 
ments of  commanders  of  vessels,  this  frequently  occurs  now, 
while  with  the  oil-lights  it  was  very  rarely  observed.  The 
electric  light  appears  to  have  had  a  considerably  greater 
range.  We  shall  refrain  from  giving  too  great  emphasis  to 
a  note  sent  us  by  a  captain  of  a  steamer,  who  asserts  that 
in  one  particular  instance,  under  favorable  circumstances, 
he  did  not  lose  sight  of  the  electric  light  until  at  a  distance 
of  forty  miles  from  Havre,  after  having  seen  the  light  of 

*  Two  hundred  aud  twelve  dollars  and  thirty  cents  was  allowed  in 
1863,  and  $57.90  in  1865,  to  M.  Serrirr  as  compensation  for  experiments 
and  models.  We  mention  these  items  in  order  to  show  the  exact  price 
of  the  regulators ;  besides,  M.  Serriu  now  sells  his  apparatus  at  $280.50, 
instead  of  $193. 

t  We  have  more  especially  consulted  the  captains  of  steamers  running 
toDunkerque,  Morlaix,  Bordeaux,  and  the  ports  of  Spain,  as  they  have 
more  opportunities  for  observing  the  lights  of  La  Heve. 


LIGHTHOUSES  OF  LA  HEVE. 

ELECTRIC  LIGHTS. 


PLATE  XLIV. 


SWITCHES. 


Bg.4. 


mttf 


SCALE. 

."  0 


nFoot. 


IVERSI-TT 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  243 

Barfleur  for  an  hour  and  a  half;  but  we  shall  call  attention 
to  the  following  statements,  selected  from  a  great  number 
of  others,  which  confirm  the  same  results : 

The  electric  light  has  generally  been  visible  at  a  greater 
distance  than  the  other  by  : 

6  to  7  miles  according  to  Captain  Fautrel. 

4  to  5  miles  according  to  Captain  Morisse. 

2  —  miles  according  to  Captain  Lemonnier. 

3  —  miles  according  to  Captain  Kebour. 

4  to  6  miles  according  to  captain  of  the  Yilledu  Havre. 
4  —  miles  according  to  Captain  Duval. 

4  to  5  miles  according  to  the  pilot,  Lecoq. 

5  to  6  miles  according  to  the  pilot,  Guerrier. 
4  —  miles  according  to  the  pilot,  Mazeras. 

Some  captains  corroborate  these  statements  by  declar- 
ing that,  at  great  distances,  when  the  lights  were  first  seen, 
the  electric  light  seemed  a  little  higher  than  the  other.  At 
some  distance  there  was  a  notable  difference  in  their  bril- 
liancy; the  electric  light  appearing  white  and  brilliant,  the 
other  red  and  smoky.  The  effect  produced  was  well  de- 
scribed by  the  picturesque  comparison  made  by  one  of  the 
pilots  of  Havre,  ( Pilot  Savalle :)  "  There  is  as  much  differ- 
ence between  the  lights  as  between  a  candle  and  a  gas- 
light." This  effect  was  moreover  distinctly  visible  from  the 
north  pier  of  Havre. 

The  statements  agreed  still  better  in  regard  to  the  light  Light  during 
during  foggy  weather.  All  the  captains  and  pilots  con-f( 
suited  by  us  declared  that  during  fog  there  was  a  great 
difference  in  the  range,  and  they  all  spoke  highly  of  the 
services  rendered  them  by  the  electric  light ;  they  assured 
us  emphatically  that  a  large  number  of  vessels  had  been 
able  to  enter  the  harbor  without  difficulty,  perceiving  the 
southern  light,  while  formerly  they  had  been  obliged  to  re- 
main outside,  the  lights  not  being  visible.  Even  before  per- 
ceiving the  electric  light,  its  presence  was  marked  by  the 
illumination  of  the  atmosphere  surrounding  it,  audits  range 
was  thus  increased,  especially  in  foggy  weather.  This  is  an 
important  advantage  of  the  electric  light,  and  may  be  of 
great  practical  utility,  as  is  shown  by  a  letter  from  Captain 
Delbeke  of  the  steamer  La  Flandre,  which  we  give  below,  as 
it  well  states  the  facts : 

"  In  the  nights  of  the  26th  and  27th  of  February,  1865,  I    statement    of 

,,,..-  ..„  .,  .,  ,     .     Captain  Delbeke. 

was  doubling  Cape  Antifer  at  1  a.  m.,  three  miles  out,  in  ' 
eighteen  fathoms  of  water,  the  point  of  the  cape  bearing  S. 
E.  J  E.    The  weather  was  very  foggy  on  shore,  but  an  ex- 
perienced seaman  could  make  out  the  point  well  enough  to 
determine  his  position.    1  was  then  eleven  miles  and  a  half 


244 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


from  the  Fecamp  light,  which  was  not  visible  for  the  fog, 
and  twelve  miles  from  LaHeve  lights,  toward  which  I  could 
steer,  as  I  saw,  tot  the  lights  themselves,  but  their  reflec- 
tion. Approaching  in  order  to  make  the  channel  and  enter 
the  inner  roadstead  of  Havre,  (it  was  then  3  a.  m.,)  I  clearly 
saw  the  electric  light  and  could  not  see  the  ordinary  light." 
Diminished  dif-  The  difference  of  range  between  electric  and  oil  lights 
£lringefog. rauge  diminishes  rapidly  when  the  fog  thickens.  Inspector-Gen- 
eral Keynaud.  in  a  report  dated  May  20, 18G3,  estimated  the 
comparative  range  of  a  fixed  light  of  the  first  order  illumi- 
nated by  oil  or  electricity  as  follows  : 


Table  of  com- 
parative range. 


Range  of  the 
unit  of  light. 

Range  in  kilometers  of  a 
first-order  fixed  light. 

Oil  :  inten- 
sity, 630 
units. 

Electricity  : 
intensity, 
3,500  units. 

Kilometers. 
0.1 
0.5 
1 
2 
3 
4 
5 

Kilometers. 
0.160 
0.93 

2.08 
4.89 
8.45 
12.9 

18.7 

Kilometers. 
0.177 
1.06 
2.40 

5.77 
10.2 
15.9 
23.4 

It  is  seen  that  even  in  a  slight  fog  the  electric  light  is  but 
little  superior  in  range  in  spite  of  the  great  difference  of 
luminous  intensity,  but  it  gains  in  proportion  to  the  clear- 
ness of  the  atmosphere.  This  result  is  also  shown  by  the 
following  table,  the  result  of  observations  made  in  1864  at 
the  light-houses  of  Honfleur,  Fatouviile,  and  Ver:  * 


Table  of  results 
of     comparative 
observations. 

Places  of  obser- 
vation. 

Distances. 

Light  ob- 
served. 

Proportion  of 
visibility  in 
100  observa- 
tions. 

Proportional 
value  of  elec- 
tricity. 

Miles. 

<  Oil 

88  ? 

Houfleur  

9.32 

1.  045 

>  Electricity, 
j  Oil  

92  s 

77  ? 

Fatouviile  

13.36 

)  Electricity. 
(Oil  

79  5 
33  ) 

1.  026 

Ver 

28.  89 

A.  > 

1.24 

}  Electricity. 

41  $ 

c  d    b  y    vertical 
sash-bars. 


Light  obstruct-     The  observations  made  at  Fatouviile  seem  afnomalous $ 
but  this  is  easily  explained,  for  one  of  the  uprights  of  the 

*  This  table  and  the  remarks  following  are  taken  from  the  report  of 
M.  Reynaud,  inspector-general,  and  dated  March  31,  1866. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  245 

lantern  of  the  northern  light-house  was  placed  in  the  direc- 
tion of  the  light  of  Honfleur,  thus  masking  a  considerable 
part  of  the  light  emanating  from  the  apparatus.  The  range 
of  the  electric  light  is,  moreover,  diminished  in  foggy 
weather,  on  account  of  its  inferior  power  of  penetration. 

This  arises  from  the  different  composition  of  the  two  lights, 
and  is  the  more  marked  as  the  fog  thickens.  Experiments 
made  at  the  central  depot  have  shown,  however,  that  if  the 
electric  light  has  an  intensity  two  and  a  half  times  greater 
than  a  light  of  colza-oil,  it  will  penetrate  fog  as  well.  As 
the  intensity  of  the  electric  lights  at  La  Heve,  compared 
with  an  oil-light,  for  surpasses  this  proportion,  we  may  be 
assured  that  the  electric  lights  will  always  be  superior  in 
range. 

Since  1865  six-disk  machines  have  been  used.    The  iuteu-    use  of -six-aisk 

-,    .,  ,    ,.        machines. 

sity  has  thus  been  considerably  increased,  and  the  relative 
range  of  the  lights  has  always  surpassed  that  shown  in  the 
preceding  tables. 

In  order  to  complete  the  comparison  of  the  two  modes  of 
producing  light,  there  are  yet  a  few  words  to  be  said  as  to 
the  expense  of  each. 

At  La  Heve,  as  we  have  already  shown,  the  electric  lights    comparison  of 
cost  $3,215.29  annually,  deterioration  of  machinery  not  in- co 
eluded.     For  the  same  period  the  oil-lights  before  the  altera- 
tion cost  $2,828.88,  distributed  as  follows :  * 

Salaries $820  25 

Fuel 77  20 

Oil 1,  800  58 

Sundry  supplies 84  53 

Keeping  apparatus  in  order 46  32 

The  expense  is  thus  greater  by  $386.41,  or  about  one- 
seventh  $  but  this  increase  of  cost  is  largely  repaid  by  the 
increase  of  intensity  of  the  lights. 

The  electric  lights  of  La  Heve  have  this  economical  ad-  "  of 

vantage,  that,  while  two  in  number,  the  expenses  are  far 
from  being  double  what  they  would  be  for  a  single  light. 
A  certain  number  of  expenses  are,  in  fact,  common  to  the 
two,  or  approximately  so,  especially  salaries,  the  extra  com- 
pensation and  allowance  for  fuel  to  the  engineers,  the  coal 
for  the  engines,  &c. 

This  is  not  the  case  when  oil  is  used,  for  then  two  lights 
will  cost  very  nearly  double  what  a  single  one  would  in  the 
same  circumstances. 

*  See  M.  Reynaud's  Memoire  sur  VEclairage  des  Cotes  de  France. 


246 


EUROPEAN   LIGHT-HOUSE    SYSTEMS, 


Estimated  cost 
of  electric  light. 


Basing  our  calculations  on  the  experience  of  1863  to  1865, 
we  estimate  the  cost  of  an  electric  light  of  5,000-burner 
intensity  as  follows : 


Nature  of  expense. 

Price. 

Quantities. 

Cost. 

Salaries  

$834  72 

Allowance  for  fuel 

77  20 

Bonus  to  engineers  

57  90 

Water.   .   . 

71  328  CO 

Coal,  per  ton  of  2,240  pounds  

$6  18 

15,  428 

43  23 

Coke,  per  ton  of  2,240  pounds 

8  69 

110,200 

434  25 

Carbon  points 

434 

393  70 

156  33 

Cotton-waste.       ... 

23 

308.  56 

32  43 

Luoricatiucr-oil  • 

38| 

440  80 

77  20 

Illuminating-oil  

27 

551 

67  55 

Grease 

25 

88  16 

10  04 

Hemp,  white-lead,  &c  

9  65 

Towels,  mops,  &c. 

11  58 

Various  supplies  and  repairs  to  ma- 
chinery       .                        ... 

156  52 

Total 

1  968  60 

Cost    of     first- 
order  oil-light. 


co?t° 

liht. 


The  average  cost  of  a  first-order  oil-light  of  630-burner  in- 
tensity is  $1,494.40,*  viz: 

Three  keepers,  (two  first  and  one  second  class) $477  68 

Fuel 48  25 

Oil - .  - ..  903  04 

Sundry  supplies 42  27 

Keeping  apparatus  in  order. 23  16 

The  electric  light  would  cost  about  $475  more  than  the 
other,  and  the  expense  would  therefore  be  increased  nearly 
one-third.  A  comparison  of  the  cost  of  the  unit  of  light  for 
oil-consuming  and  electric  lights  may  easily  be  made  from 
the  preceding,  and  the  figures  given  by  Inspector-General 
Eeynaud  are  verified.  At  La  Heve,  as  the  expense  of  the 
electric  light  amounts  to  $3,215.34  for  4,135  hours7  illunil- 

e  4,055  x  5,000+80  x  10,000, 
nation,  and  a  mean  intensity  or  -  — /T135 — 

or  5,097  burners,  taking  into  account  the  time  double  light 
of  was  produced;  the  unit  of  light  sent  to  the  horizon  by  each 

$3,215.34 
light-house  costs,  therefore,  2  x  5  097  x  4  155  =  $^.000076. 

The  cost  of  the   unit  of  light  produced  by  the  oil-con- 

*  See  M.  Reynaud's  Memoire  sur  I'ficlairage  des  Cotes  de  France. 


LIGHTHOUSES  OF  LA  HEVE. 

ELECTRIC  LIGHTS. 
ELECTRIC  REGULATOR. 


PLATE  XLV, 


SCALE. 

6 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  247 

suming  light-houses    before  their   alteration   amounts   to 

r.  =  $0.000576  *  which  shows  that  the  unit 
£  X  oou  X  o,JUu 

of  light  at  the  light-houses  at  La  Heve  costs  about  seven 
times  less  than  that  of  oil-consuming  lights.    If,  on  the  con 
trary,  we  consider  a  single  electric  and  a  single  oil  consum- 
ing light,  the  unit  sent  to  the  horizon  would  cost  for  the 

former  F  ,   or  $0.0000952.   and  for  the  latter, 

O,UUU  X  4,-LoO 

!n'49t'tnn>  or  $0.000608.  The  difference  of  cost  is  therefore 
GoU  x  o,yuo 

somewhat  more. 

Conclusion. — Since  the  first  establishment  of  the  electric    Reca  itulatiou 
light,  six  years  ago,  sufficient  time  has  elapsed  to  give  an 
exact  idea  of  its  value  for  coast  illumination. 

Navigators  acknowledge  with  pleasure  the  excellent  serv- 

,    .      ,.    ,   .  ,,  .,  ,  Satisfaction   of 

ice  which  the  electric  lights  render  them;  the  advantages  navigators, 
of  the  system  have  been  keenly  appreciated,  the  range  of 
the  lights  is  sensibly  increased,  especially  during  somewhat 
foggy  weather,  thus  allowing  a  great  number  of  vessels  to 
proceed  on  their  course  and  enter  the  harbor  at  night,  which 
they  would  not  have  been  able  to  do  with  the  oil-light. 
The  light,  which  at  first  was  not  as  steady  as  could  be 

Steadiness      of 

wished,  acquired  a  remarkable  steadiness,  thanks  to  im-  tto  light. 
provemeuts  in  the  apparatus  and  the  experience  acquired 
by  the  keepers.  The  fears  which  were  entertained,  a  priori, 
on  account  of  the  delicacy  of  some  of  the  apparatus,  have 
not  been  justified  in  practice.  Accidents  have  been  rare, 
extinctions  short  and  few;  two  only  of  the  latter  during  the 
period  of  six  years  being  of  notable  duration;  one,  of  one 
hour,  was  the  consequence  of  an  accident  to  a  steam-en- 
gine ;  the  other,  of  four  hours,  seems  to  have  been  mali- 
ciously caused.  Under  these  circumstances  there  seems 
but  little  reason  to  be  troubled  about  possible  accidents. 

Still  there  are  some  disadvantages  inherent  in  the  system  Disadvantages. 
of  electric  illumination  which  necessarily  limit  its  applica- 
tion. A  considerable  space  is  required  for  the  steam-en- 
gines and  the  magneto-electric  machinery,  for  storing  coal, 
coke,  oil,  &c.,  and  for  collecting  and  preserving  the  water 
for  the  engines. 

Finally,  the  repairs  of  apparatus  in  use  require  special 
workmen,  not  usually  found  in  the  vicinity  of  light-houses. 

*  These  calculations  suppose  the  electric  light  in  operation  4,135  hours, 
and  the  oil-consuming  lights  3,900  hours,  because  under  these  conditions 
the  expenses  were  estimated. 


248  EUKOPEAN    LIGHT-HOUSE    SYSTEMS, 

The  keepers  usually  can  attend  only  to  current  repairs;  the 
more  important  ones  have  to  be  done  in  workshops  better 
appointed  than  those  attached  to  light-houses.  In  case  of 
an  accident  of  some  importance,  the  magneto-electric  appa- 
ratus can  only  be  repaired  by  the  Alliance  Company.  The 
lamps,  under  the  same  circumstances,  have  to  be  sent  to 
M.  Serrin  at  Paris.  It  is  true  that,  as  there  are  several 
regulators  at  the  light-houses,  one  of  them  may  be  spared, 
so  that  the  rare  accidents  which  occur  to  these  apparatus 
never  cause  but  a  few  seconds'  interruption  of  the  light. 
Proper  situa-  We  therefore  think  that  in  a  great  number  of  cases,  espe- 

t:uu  lor    electric 

cially  in  those  of  light-houses  in  the  sea,  or  distant  from 
important  centers  of  population,  or  not  easily  accessible, 
the  substitution  of  electric  light  for  that  produced  by  the 
combustion  of  colza-oil  would  be  disadvantageous,  or  even 
impossible.  But  as  this  substitution  offers  great  advan- 
tages to  navigation,  it  seems  advisable  to  adopt  it  for 
light-houses  favorably  situated  ;  that  is  to  say,  where  there 
is  plenty  of  space,  and  they  are  sufficiently  near  to  cities  or 
easily  accessible.  The  French  light-house  administration 
have  already  established  a  second  one  at  Grisnez. 

England,  after  having  first  tried  the  electric  light  at 
Dungeness,  is  about  to  establish  others  at  South  Foreland 
and  Lowestoft.  The  attention  of  other  governments  is  also 
drawn  to  this  matter,  and  it  appears  probable  that  the 
example  of  England  and  France  will  be  followed. 

The  change  will  cause  a  slight  increase  in  the  running 
expenses,  but  the  difference  is  not  so  great  as  to  cause  hesi- 
tation when  the  increase  of  intensity  and  of  range  is  con- 
sidered. 


CAPE   GRIS-NEZ  LIGHTHOUSE. 

LLECTRIC  LIGHT.  PLATE  XLVI. 


PLAN    AND     SECTION  , 
SHOWING  ARRANGEMENTS    OF  LANTERN   AND   LENSES 
FOR    THE   ELECTRIC  AND   OIL  LIGHTS. 


t  *          3SOA»LE-   *  <  r 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  249 

I  had  no  opportunity  of  visiting  any  of  the  light- ships    Notes  on  the 
belonging  to  the  French  service.    These  are  ten  in  number,  ship  service.  ° 
one  of  which  carries  a  revolving  red  light.     Most  of  them 
are  on  the  southwest  coast  of  France.    I  have  learned,  how- 
ever, the  following  particulars  in  regard  to  the  regulations, 

A  light-ship's  crew  consists  of  a  captain,  mate,  boatswain,  oew. 
(maitre  $  equipage,}  and  seamen.  They  are  under  the  orders 
of  the  engineers  or  such  superintendents  as  they  may  be  as- 
signed to.  None  can  enter  this  service  but  regular  sailors, 
who  have  had  at  least  three  years'  service  in  the  navy,  and 
who  know  how  to  read  and  write. 

Appointments  are  made  by  the  prefect  on  nomination  of   Appointments. 
the  engiueer-in-chief. 

The  salaries  are  fixed  by  the 'Ministry  of  Public  Works,    Salarie8 
and  are  subject  to  a  deduction  of  3  per  cent.,  which  is  ap- 
plied to  the  marine-hospital  fund. 

The  captain  is  responsible  for  the  service  of  the  light,  and    Duties  ot  tim 
has,  on  board  ship,  all  the  rights  of  captain  of  the  merchant- capta 
marine.    He  keeps  the  log  and  all  the  correspondence.    In 
his  absence  his  place  is  taken  by  the  mate. 

The  boatswain  sees  that  the  captain's  orders  are  executed,    of   the  boat- 
and  he  is  particularly  charged  with  the  order  and  cleanli- 8wam> 
ness  of  the  vessel.     He  is  not  required  to  assist  in  the  man- 
ual labor  of  cleaning  the  vessel,  but  he  directs  the  details 
of  the  work  and  keeps  watch  like  the  seamen  only  in  excep- 
tional cases  to  be  judged  of  by  the  engineers.    In  case  of  ab- 
sence his  place  is  supplied  by  a  sailor  selected  by  the  cap- 
tain. 

The  captain  and  mate  have  alternately  fifteen  days  of   services  of  cap- 
service  and  fifteen  days  ashore  $  the  sailors  pass  alternately    of  Sew!1*' 
a  month  afloat  and  fifteen  days  ashore.    These  leaves  are, 
on  some  vessels,  reduced  one-half  during  the  bad  season. 

While  ashore  the  officers  and  sailors  are  at  the  disposal    under  orders 
of  the  engineer-in-chief,  and  cannot  quit  their  places  of  resi-  ashorl!ne€ 
dence  without  authority.    They  are  obliged  to   obey  any 
orders  that  may  be  given  them,  either  to  return  aboard,  to 
attend  to  embarkations,  or  to  any  of  the  lights  or  beacons 
of  the  department. 

The  captain  is  responsible  for  the  provisions,  and  keeps 
the  account  of  them.  He  may  detail  a  seaman  for 'cook,  or 
decide  that  all  shall  take  their  turn. 

THE  INTERNATIONAL   EXHIBITION   AT  VIENNA, 

1873. 

From  Paris  I  proceeded  to  Vienna  by  way  of  Ulm,  Augs- 
burg, and  Munich.  I  intended  to  have  gone  via  Venice,  and 


250  EUROPEAN   LIGHT-HOUSE    SYSTEMS. 

Trieste,  but  when  I  arrived  at  the  foot  of  the  Saint  Gothard 
Pass,  exaggerated  accounts  of  the  cholera  prevailing  at  the 
former  place,  deterred  me  from  taking  that  route. 

On  arriving  at  Vienna  and  presenting  myself  at  the  lega- 
tion of  the  United  States,  I  was  received  in  the  most  cordial 
manner  by  the  Hon.  Mr.  Jay,  the  American  Minister,  who 
proffered  every  assistance  in  his  power. 

Buildings.  The  exhibition  buildings  were  on  a  grand  scale,  and.  it 

was  said  the  Austrian  government  had  already  expended 
on  this  exhibition  more  than  20,000,000  gulden,  or  more 
than  $10,000,000. 

Most  of  the  departments,  particularly  the  department  of 
machinery,  were  well  filled  $  and  the  same  may  be  said  of 
the  spaces  allotted  to  the  different  countries,  with  a  few 
exceptions,  which  include,  I  regret  to  say,  that  assigned  to 
the  United  States.  From  some  cause,  probably  our  re- 
moteness from  Vienna,  the  American  exhibition  was  ex- 
tremely meager. 

hiwtione%°rtah5      *  was  disappointed  at  the  small  number  of  articles  of 

houses°and?iavi  ""  Merest  pertaining  to  light-houses  and  other  aids  to  naviga- 

gaticn.  tjon.  and  those  which  were  exhibited  were  mainly  sent  by 

the  French  and  Austrian  governments  and  the  lens  makers 

of  Paris. 

Display  by  the     The  "Department  of  Public  Works"  of  France  had  a 


of  Public  fine  display  of  models  and  drawings  of  light-houses  in  con- 
nection with  an  extensive  exhibition  of  views  and  models 
of  other  works  of  the  Corps  des  Fonts  et  Chaussees.  I  did 
not  observe  anything  particularly  novel  in  the  construction 
of  the  light-houses,  but  they  all  showed  evidences  of  the 
good  taste  in  architecture  which  characterize  all  works  of 
the  French  engineers. 
Light-houses  The  following  is  a  list  of  the  light-houses  represented: 

represented. 

Phare  de  la  Palmyre,  a  wrought-iron  range  or  leading 
light-house  on  a  screw-pile  foundation. 

Phare  de  Royan,  a  masonry  range  or  leading  light  built 
in  alternate  courses  of  stone  and  brick,  the  upper  portion 
of  the  tower  being  of  a  peculiar  shape,  for  the  purpose,  most 
likely,  of  serving  as  a  day-mark. 

Phare  des  Roches-Douvres,  a  wrought  (plate)  iron  coast- 
light,  very  much  like  the  Phare  de  la  Nouvelle  Calcdonie, 
shown  in  M.  Keynaud's  U  Eclairage  des  Cotes  de  France. 

Phare  du  Four,  a  k<  rock"  light-house. 

Phare  cPAr-men,  a  coast-light  of  stone  masonry—  a  rock- 
station. 

Submarine     The  Corps  des  Ponts  et  Chaussees  had  also  models  of  sub- 
foundations.       marine  foun(iations  for  harbor  light  houses  built  on  shoals 


SUBMARINE  CONCRETE  FOUNDATION 

FOR 
A  HARBOR  LIGHTHOUSE.       PLATEXLVII. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  251 

or  bars,  very  much  like  those  which  I  had  designed  for  our 
lights  in  Long  Island  Sound,  Delaware  Bay,  Chesapeake 
Bay.  and  other  localities  where  light-houses  are  subject  to 
injury  from  ice. 

Two  methods  were  represented,  in  one  of  which  the  iron 
tube  or  shell  is  left  in  place  after  it  is  filled  with  concrete; 
the  other  showed  a  cylindrical  foundation  of  concrete  made 
by  means  of  a  movable  mould,  which  is  turned  around  an 
axis,  as  represented  by  Plate  XL  VII. 

Several  novelties  were  shown  by  the  lens-manufacturers 
of  Paris. 

M.   Lepaute   exhibited   a  third-order  revolving  lens,  a    Lens  exhibited 
duplicate  of  the  one  which  I  have  described  as  exhibited  to 
me  at  his  manufactory  at  Paris,  in  which  one-half  showed  a 
fixed  light  and  the  other  half  was  divided  into  eight  con- 
secutive flash-  panels. 

This  would  be  a  striking  characteristic  in  waters  where 
there  are  already  many  lights,  and  where  in  placing  a  new 
one  it  becomes  necessary  to  distinguish  it,  particularly  if 
the  flash  panels  were  covered  with  red  screens,  which  would 
tend  to  equalize  the  range  of  the  fixed  light  and  the  flashes. 

This  lens  was  furnished  with  a  mechanical  or  pump  lamp, 
with  a  three-wick  burner  of  the  kind  recently  adopted  by 
the  French,  which  is  adapted  to  the  use  of  either  colza  or 
mineral  oil,  though  the  latter  is  designed  to  be  used  in  it. 

The  clock-work  operating  the  pumps  was  specially  de-  re^^nw^rk  for 
signed  for  revolving  lights  by  M.  Lepaute,  and  was  remark- 
able for  the  small  space  required  for  it,  viz,  not  more  than 
six  inches  in  diameter,  a  great  improvement  for  small  orders 
of  lights. 

Sautter,  Lemounier  &  Co.  exhibited  photographs  of  the 
flame  from  the  Farquhar  burner,  (the  patent-right  of  which 
is  owned  by  this  firm,)  and  the  following  lenticular  ap- 
paratus : 

1st.  A  range  light  or  feu  de  direction,  showing  alternately    Eange-iigkt  by 
red  and  green.    This  apparatus  was  composed  of  a  dioptric  nSr*6!'          "" 


and  catadioptric  lens  for  fixed  light,  embracing  150°,  a  cata-  " 
dioptric  reflector  placed  in  the  dead  angle,  and  two  groups 
of  vertical  prisms  arranged  in  front  of  the  apparatus  for 
fixed  light,  in  the  space  on  either  side  of  the  axis  and  out- 
side the  angle  which  it  is  required  to  light.  These  elements 
are  so  calculated  that  they  concentrate  the  light  from  the 
fixed-light  lens  and  distribute  it  as  uniformly  as  possible 
throughout  an  angle  of  45°.  Between  the  fixed-light  ap- 
paratus and  the  vertical  prisms  there  is  a  circular  screen, 
composed  of  three  plates  of  glass,'  each  embracing  75°. 


252  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Red  and^  green,  The  two  outer  plates  are  red,  the  middle  one  green.  The 
frame-work  supporting  this  screen  receives  an  intermittent 
oscillating  movement,  so  that  the  light  changes  rapidly 
from  one  color  to  the  other,  preserving  a  constant  color  for 
a  determinate  time. 

The  screen  passes  through  an  arc  of  75°  in  four  seconds  ; 
then  it  is  at  rest  for  sixteen  seconds,  and  then  repeats  the 
motion  in  an  opposite  direction,  and  again  becomes  motion- 
less. This  movement  brings  successively  before  each  part 
of  the  apparatus  first  the  red  and  then  the  green  panes,  so 
as  to  produce  the  characteristic  required. 

pier-  light  by  2d.  A  pier-light,  (fanal  de  jettee.)  This  light  presents  a 
very  characteristic  appearance,  and  if  placed  near  a  town 
it  would  never  be  confounded  with  ordinary  street  and 
house  lights.  The  apparatus  is  composed  of  an  ordinary 
fourth-order  lens  for  fixed  light,  around  which  revolves  a 
drum  composed  of  vertical  plauo-cylindric  lenses,  each  of 
which  receives  a  luminous  beam  18°  wide,  and  concentrates 
it  within  6°,  thus  diminishing  the  divergence  and  augment- 
audnunfla8iifespro  ing  the  intensity  in  proportion  of  1  to  3.  This  drum 
reaches  to  just  above  the  central  lens  of  the  apparatus,  so 
that  all  the  upper  prisms  preserve  the  appearance  of  a  fixed 
light  of  sufficient  intensity  to  be  seen  at  least  twelve  miles. 
On  account  of  the  interposition  and  regular  revolution  of 
the  movable  lenses,  the  light  presents  a  series  of  dilatations 
like  equidistant  pulsations,  which  gives  it  a  very  character- 
istic appearance.  Experiments  made  to  determine  the  best 
interval  between  two  pulsations  showed  that  it  ought  not 
to  be  less  than  a  second  and  a  half,  for  if  the  flashes  were 
nearer  together  they  might  be  confounded  with  the  natural 
scintillation  which  lights  near  water  have,  under  certain 
atmospheric  conditions. 

The  lens  exhibited  was  of  the  fourth  order,  but  fifth  and 
sixth  order  lenses  of  the  same  kind  can  be  easily  con- 
structed. 

le^for^eiSc     3<*'  A  ver^  fine  scintillating  lens  for  electric  light,  for  the 
light,  following  description  of  whieh  I  am  indebted  to  the  courtesy 

of  Messrs.  Sautter,  Lemonnier  &  Co.: 

u  In  most  of  the  apparatus  for  electric  light  hitherto  con- 
structed, the  optical  part  is  composed  of  a  cylindrical  lens 
for  fixed  light  30  centimeters  in  interior  diameter,  before 
which,  in  flashing  lenses,  prisms  of  vertical  elements  are  made 
to  pass.  We  prefer  to  increase  the  diameter  of  the  lens, 
and  that  for  several  reasons. 
8  Same  '  u  1st.  In  case  there  should  be  used  a  more  intense  elec- 


tor of  the  lens.    trie  light  than  the  one  produced  by  the  machines  now  em- 
ployed, (such  a  one,  for  instance,  as  is  given  by  the  new  ma- 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  253 

chines  of  Gramme,)  it  would  become  necessary  for  the  pres- 
ervation of  the  glass  that  it  should  be  farther  removed  from 
the  luminous  focus. 

"  2d.  Because  a  larger  apparatus  is  easier  to  keep  in 
order. 

"  3d.  Because  the  larger  the  apparatus  the  less  the  inevi- 
table variations  in  the  position  of  the  luminous  point  will 
affect  the  direction  of  the  rays  emerging  from  the  lens. 

"The  apparatus  (shown  in  Plate  XL VIII)  is  composed  of   ^en 
a  cylindrical  lens  for  fixed  light,  75  centimeters  in  interior 
diameter,  with  upper  and  lower  catadioptric  zones.     The 
metal  supports  of  the  central  part  are  diagonal,  so  that  in 
no  direction  does  the  frame  completely  obstruct  the  light. 

"A  polygonal  drum,  composed  of  twenty-four  vertical  piano- 
cylindric  lenses,  envelops  the  apparatus  from  the  top  down 
to  just  below  the  central  lens,  and  is  made  to  revolve 
regularly,  by  means  of  clock-work  placed  in  the  pedes- 
tal of  the  apparatus.  Each  lens  receives  a  luminous  beam 
15°  wide,  and  concentrates  it  within  5°.  In  the  apparatus 
which  was  exhibited,  the  drum  makes  a  complete  revolution 
in  120  seconds,  so  that  the  flashes  succeed  each  other  every 
five  seconds.  The  duration  of  the  flash  is  half  the  interval 
between  the  flashes,  and  the  fixed  light  of  less  intensity  is 
constantly  visible.  The  intensity  of  the  former  is  about 
eight  times  as  great  as  the  latter.  The  proportions  remain 
the  same  whatever  may  be  the  intervals  between  the  flashes ; 
if  the  interval  is  increased  the  absolute  duration  of  the  flash 
is  increased  in  the  same  proportion. 

"  In  oil-lights  a  remedy  is  sought  for  the  short  duration 
of  the  flashes  by  increasing  the  diameter  of  the  flame.  This 
disadvantage  will  not  exist  in  electric  lights  arranged  as  we 
have  described,  the  divergence  being  caused  not  by  the  di- 
ameter of  the  luminous  focus,  but  by  the  form  of  the  lens, 
and  existing  only  in  the  horizontal  plane— that  is,  without 
loss  of  light. 

"  The  electric  lamp  constructed  by  M.  Serrin  is  placed  on 
a  revolving  plate,  eccentric  with  regard  to  the  platform  of 
the  apparatus-.  This  plate  can  receive  two  lamps  back  to 
back.  It  has  two  rails  on  which  the  lamps  slide,  and  which 
are  prolonged  on  a  platform  attached  to  that  of  the  appa- 
ratus, and  jutting  out  behind.  The  plate  can  be  held  by  a 
spring-catch  in  two  positions  diametrically  opposite.  In  the 
first  of  these  positions,  one  of  the  lamps  is  at  the  focus  of 
the  apparatus,  and  the  other  in  position  to  be  attended  to 
and  its  carbons  changed.  In  the  second  position  the  reverse 
takes  place.  The  current  passes  and  the  lamp  is  lighted  of 
itself  when  placed  in  position. 


254 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


"  This  apparatus  should  be  placed  in  a  lantern  having 
flat  steel  diagonal  sash-bars  with  an  inclination  correspond- 
ing to  that  of  the  lens-frame." 

Besides  the  optical  apparatus  exhibited  by  Messrs.  Saut- 
ter, Lemonnier  &  Co.,  they  displayed  an  iron  light-house 
tower  of  peculiar  construction  and  excellent  workmanship. 
Translation  of  The  following  description  of  it,  is  translated  from  the 


Ir  on  light 
house  tower. 


description.  a 


"  Annales  Industrielles  »  of  September  28,  1873  : 


Formation 
tower. 


"  The  tower  shown  in  elevation,  (Fig.  1,  Plate  XLIX,)  rests 
on  a  foundation  formed  of  eight  radiating  iron  ribs  bound 
together  by  masonry,  and  rising  about  5  meters  above  the 
terrace  on  which  the  structure  rests.  It  is  composed  of  a 
sheet-iron  cylinder  12m.50  high,  with  a  winding  stairway 
inside,  and  strengthened  by  eight  buttresses  or  ribs  of  iron. 
These  buttresses  take  the  form  of  brackets  above  and  sup- 
port a  cast-iron  gallery  which  extends  around  the  lantern. 
of  "  The  cylinder  or  central  tower  is  formed  of  five  sheet- 
iron  sections  Om.006  thick,  each  2m.50  high  and  lm.80  in 
diameter.  The  interior  of  each  is  occupied  by  twelve  steps 
of  corrugated  sheet-iron,  the  upper  part  of  which  forms  a 
landing ;  riveted  corner-pieces  hold  them  against  the  outer 
envelope,  and  a  cylinder  Om.40  in  diameter  supports  them 
at  the  center.  The  sections  fit  into  each  other  and  are  held 
together  by  rivets.  Each  weighs  1,500  kilograms.  The 
vertical  ribs  are  each  formed  of  four  pieces,  one  above  the 
ol  her,  and  they  are  bound  together  by  three  bands  or  rigid 
horizontal  crowns  placed  at  equal  vertical  distances. 

u  The  tower  is  mounted  without  exterior  scaffolding  by 
means  of  a  gallows-crane  supported  on  the  last  section  put 
in  place.  It  is  shown  in  detail  in  Fig.  4.  It  is  composed 
of  an  upright  formed  of  two  T-irons  connected  by  tie-pieces 
and  held  at  the  lower  end  by  a  cast-iron  pivot.  The  arm, 
formed  of  two  flat  pieces  of  iron  connected  by  braces,  carries 
two  pulley-blocks  and  a  hook  intended  to  receive  a  tackle. 
The  fall  of  this  tackle  is  conducted  from  the  pulley-blocks  to 
the  upright  axis  of  the  crane.  It  descends  vertically  in  this 
axis,  traverses  the  pivot,  and  a  final  pulley 'carries  it  to  a 
windlass  used  for  hoisting. 

Placing  the  first     "  It  was  first  necessary  to  place  the  first  section  on  the 
section."  foundation,  an  operation  which  was  somewhat  difficult,  as 

the  space  for  maneuvering  was  small.  In  order  to  effect 
it  the  crane  was  used,  it  being  set  up  on  the  foundation  and 
supported  by  guys.  Eaised  to  the  required  height  the  sec- 
tion was  brought  into  place  by  rotating  the  crane.  This 
first  operation  would  in  general  practice  offer  no  difficulty, 


Crane. 


Crt 


n 

5 

30 

o 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


255 


Tools. 


and  could  be  done,  according  to  circumstances,  by  any  other 
means  than  that  we  have  just  described.  But  when  this 
section  is  once  placed  and  solidly  bolted  to  the  foundation, 
the  mounting  should  continue  and  be  finished  without  the 
aid  of  any  scaffolding  or  support  taken  outside  of  the  tower 
itself.  The  mounting  comprises,  first,  the  placing  of  the  Mounting. 
iron  tube  or  the  superposition  of  the  sections  of  which  it  is 
composed,  and  which,  as  we  have  said,  weigh  about  1,500 
kilograms  each ;  second,  the  placing  of  the  ribs,  rings, 
brackets,  galleries  forming  the  frame-work,  and  the  crown- 
ing of  the  structure  with  the  lantern  and  apparatus.  These 
latter  pieces  are  relatively  light,  and  can  be  raised  to  place 
"by  means  of  falls  attached  to  the  upper  part  of  the  central 
tube.  If  the  tower  is  not  very  high  the  most  sinlple  mode 
of  mounting  consists  in  first  superposing  all  the  sections, 
and  then  fitting  the  ribs  and  other  pieces  of  the  frame- 
work. When  the  tower  is  high  it  is  prudent  to  carry  on  at 
the  same  time  the  mounting  of  the  tube  and  the  placing  of 
the  ribSv.which  strengthen  it. 

"The  tools  employed  are: 

"  The  crane  above  described,  with  an  extra  pulley  and  a 
windlass  on  the  ground ; 

u  A  movable  scaffold  shown  in  Fig.  5  5 

"  Falls  and  cordage. 

"  The  successive  operations  are : 

"Baising  and  putting  in  place  the  sections 5 

u Bolting  the  sections  together; 

"Baising  the  crane  after  the  placing  of  each  section; 

"  Lowering  and  raising  the  movable  scaffold  for  each 
section  placed;  that  is  to  say,  once  before  to  raise  the 
crane  and  put  it  in  position,  and  once  after  to  bolt  the  sec- 
tions together. 

"  The  placing  of  the  ribs,  the  rings,  the  upper  gallery, 
and  finally  the  lantern  and  illuminating-apparatus. 

"  We  have  already  described  the  crane  and  the  way  it  is 
used  to  mount  the  first  section.  It  is  used  similarly  to 
mount  the  other  sections,  with  this  difference:  that  instead 
of  placing  it  on  the  foundation,  it  is  set,  by  means  of  cast- 
iron  supports,  on  the  last  section  placed.  The  bolting  of 
the  sections  is  done  by  means  of  the  movable  scaffold  at- 
tached to  pulleys  suspended  from  the  summit  of  the  tube 
already  mounted.  The  raising  of  the  crane  is  shown  in 
Fig.  3,  and  is  effected  as  follows :  Two  falls  are  attached  to 
the  top  of  the  section  and  each  side  of  the  foot  of  the  crane, 
to  hooks  made  for  the  purpose.  The  support  c  is  unbolted, 
it  is  remounted  and  fixed  to  the  top  of  the  last  section;  at 


Operations. 


Raising      t  h  o 
crane. 


256  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

the  bottom  of  the  saihe  section  is  placed  the  guide-support 
d,  which  obliges  the  crane  to  ascend  vertically.  Finally, 
when  it  is  raised  as  far  as  desired,  the  support  of  the  pivot 
/is  bolted  and  the  operation  terminated. 

scaffold.  uThe  lowering  and  raising  of  the  scaffold  is  done  by 

hand,  by  men  placed  on  the  scaffold  itself.  The  raising  of 
the  ribs  and  all  the  other  parts  of  the  central  tube  is  done 
by  hand  with  pulleys.  The  putting  of  them  in  place  and 
the  bolting  or  riveting  of  them  is  done  by  means  of  the 
movable  scaffold.  For  all  these  operations  six  men  are 
quite  sufficient,  and  no  greater  number  was  employed  at 
Vienna  during  the  entire  mounting. 

''The  ease  and  economy  of  mounting,  is  not  the  sole 
advantage  of  the  system  of  constructing  iron  towers  adopted 
by  Messrs.  Sautter,  Lemonnier  &  Co.,  and  applied  by  them 
to  towers  of  all  dimensions.  But  in  this  article  we  have 
only  wished  to  call  attention  to  the  interesting  fact  that  an 
edifice  of  great  height  can  be  rapidly,  surely,  and  inexpen- 
sively set  up  by  a  very  few  men,  and  without  the  aid  of 
scaffolding." 
Lenf.-arpnrr.tuB  Barbier  &  Fenestre  had  on  exhibition  the  following  lens- 

cxhibitedbyBar-  „ 

lier  &  Fenestre.  apparatus : 

A  third-order  apparatus  flashing  30" — 30",  with  hydraulic 
Funck  lamps. 

A  fourth- order  flashing  apparatus,  with  Doty  lamps  and 
a  new  mechanical  arrangement. 

A  fifth-order  apparatus  F.  V.  F.,  2'— 2',  180°. 

A  sixth-order  range-light,  with  two  prisms  so  arranged 
as  to  permit  of  an  accurate  adjustment  of  the  direction  in 
which  the  light  is  thrown. 

They  had  also  a  Doty  four-wiok  lamp  with  a  clock-work 
pump. 

_  Models  of  swed-  The  Swedish  exhibition  contained  two  models  of  iron 
light-houses  resembling  ours  on  the  Florida  reefs.  Instead, 
however,  of  the  socket-joints  which  we  have  used,  the  col- 
umns are  connected  together  by  means  of -flanges  and  bolts. 
Between  the  flanges  are  placed  stout  wrought-iron  disks, 
having  projections  to  which  are  fastened  the  horizontal, 
radial,  and  peripheral  braces.  The  lugs  or  ears  to  which  the 
tie-rods  were  made  fast  were  on  the  upper  or  lower  side  of 
the  flanges,  as  the  strain  was  to  be  downward  or  upward; 
in  other  words,  the  flanges  took  upon  themselves  the  strains 
upon  those  lugs. 

These  arrangements,  which  are  shown  in  Figs.  28  and  29, 
are,  I  think,  improvements  in  the  modes  commonly  in  use 
for  similar  structures. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Iii  Fig.  28,  A  A  are  two  hollow  cast-iron  columns  fas- 
tened together  by  bolts  through  flanges;  a,  ear  to  which  the 
tie-rods  1)  are  secured;  c,  large  link  through  which  the 
small  link  d  is  passed ;  e,  wrought-irou  plate  between 
flanges. 

Fig.  28. 


257 


Details  of  Swedish  light-house.    Elevation. 
In  Fig.  29,  A  is  the  column  ;  a  «,  ears  for  the  attachment 
of  the  tie-rods ;  ///,  radial  and  peripheral  struts  of  rolled 
iron  fastened  to  wrought-iron  plate  e  6,  which  is  held  be- 
tween the  columns  as  shown  in  the  elevation,  Fig.  28. 

29. 


Details  of  Swedish  light-house.    Section. 

In  the  Austrian  part  of  the  exhibition  was  a  "Xebelhorn,"    Austrian 
S.  Ex.  54 17 


258  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

or  fog-trumpet  operated  by  steam  ;  of  this,  however,  I  could 
learn  but  little  except  what  was  contained  in  tlie  account 
given  in  the  official  catalogue,  of  which  the  following  is  a 
translation  : 
Translation  of     «« This  apparatus  has  been  constructed  at  Trieste,  after 

description. 

the  designs  of  G.  Ainadi,  engineer. 

"  In  foggy  weather  it  is  impossible  to  bring  to  the  notice 
of  mariners  the  threatening  or  desired  proximity  of  land, 
by  means  of  light-houses  or  light-signals  in  general.  It 
therefore  becomes  necessary  to  carry  sound  far  over  the 
sea  by  means  of  vigorous  acoustic  apparatus,  and  thus 
to  advise  the  mariner  that  he  is  approaching  the  coast. 
Several  kinds  of  apparatus  constructed  for  experimental 
purposes,  and  to  which  were  applied  the  shrill  notes  of  the 
whistle,  could  not,  just  on  account  of  the  high  pitch  of  the 
sound,  answer  the  purpose,  and  the  sounds  were  lost  at  a 
short  distance  from  the  coast. 

uln  this  new  fog-signal  there  are  deep  notes,  formed  like 
those  of  an  organ,  by  means  of  movable  metallic  reeds  vi- 
brated by  steam,  and  they  are  sent  out  in  a  given  direction 
through  a  trumpet  or  augmentor  of  sound.  This  signal  has 
been  heard,  according  to  the  experiments  made,  as  far  as 
sixteen  nautical  miles. 

"In  this  apparatus,  (a  similar  one  is  in  operation  at 
Trieste.)  the  notes  are  formed  automatically  by  means  of 
a  steam-engine  at  given  intervals,  and  the  apparatus  is 
turned  at  the  same  time  on  a  vertical  axis  to  reach  all  points 
of  the  horizon  in  a  uniform  manner." 

After  my  return  to  Paris,  I  wrote  to  the  Hon.  Mr.  Jay, 
and  requested  him  to  be  good  enough  to  procure,  if  tlie 
Austrian  government  would  be  pleased  to  communicate  the 
information,  drawings  and  descriptions  of  this  fog- trumpet, 
of  a  reflector  which  I  had  also  observed  in  the  Austrian 
part  of  the  exhibition,  and  of  the  Austrian  buoys.  A  few 
by  the  Austrian  days  ago  I  had  the  great  pleasure  of  receiving  from  Mr. 
8Dt'  Jay,  through  the  State  Department,  a  package  containing 
the  desired  drawings  and  descriptions ;  also  copies  of  cor 
respondence  between  himself  and  the  Austrian  Minister  of 
Foreign  Affairs,  in  regard  to  my  request,  and  of  which  the 
following  are  copies  and  translations: 

Letter  of  Hon.  "THE   AMERICAN   LEGATION   AT   VIENNA, 

Mr- Jay-  "February  23,  1874. 

"  DEAR  MAJOR  ELLIOT  :  In  acknowledging  your  note  of 
January  30,  I  am  happy  to  be  able  to  send  you,  as  I  do  by 
this  post,  through  the  State  Department,  a  roll  which  I  re- 
ceived this  morning  from  the  Foreign  Office. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS,  259 

"  I  annex  a  translation  of  the  note  of  the  Count  Andrassy 
and  a  copy  of  my  reply. 

"  You  will  see  that  the  Ministry  of  Commerce  is  prepared 
to  appreciate  the  drawings  and  plans  which  you  had  pro- 
posed to  send,  and  which  your  note  leads  me  to  expect 
presently.  Should  there  be  any  others  that  you  think  would 
be  new  and  interesting  to  this  government  and  which  there 
is  no  objection  to  communicating,  I  hope  you  will  send  them. 
Not  only  the  Foreign  Office,  but  all  the  Ministers  here,  are 
so  obliging  in  furnishing  promptly  and  gracefully  all  infor- 
mation asked  for,  and  extending  facilities  to  our  officers, 
that  I  am  always  glad  of  an  opportunity  of  reciprocating 

their  courtesies. 

*  *  *  *  *  #  * 

il  I  am,  dear  sir,  faithfully  yours, 

"JOHN  JAY. 
"  Major  GEORGE  H.  ELLIOT, 

11  Light- House  Board,  Washington." 

[Translation.] 

"  The  undersigned,  Minister  of  the  Imperial  House  and    Translation  oi 
for  Foreign  Affairs,  is  only  to-day  enabled  to  place  at  the  dis-  trla^MiS^to 
posal  of  Mr.  John  Jay,  Envoy  Extraordinary  and  Minister  Hon<  Mr' Jay' 
Plenipotentiary  of  the  United  States  of  America,  in  compli- 
ance with  his  esteemed  notes  of  20th  August  and  13th  De- 
cember last,  the  drawings  and  description  transmitted  by 
the  Imperial  and  Royal  Ministry  of  Commerce. 

"  a.  Of  the  fog-horn  exhibited  at  Vienna  in  the  year  1873 ; 

"  b.  Of  the  parabolic  reflector  of  Professor  Osnaghi  ex- 
hibited on  the  same  occasion  ; 

"  c.  Of  the  buoys  in  use  upon  the  Austrian  sea-coast. 

"  The  Minister  of  Commerce,  to  whom  the  compliance  with 
the  wish  of  the  Envoy  has  afforded  especial  pleasure,  has  at 
the  same  time  requested  the  undersigned  to  plead  with  the 
Envoy,  as  excuse  for  the  delay  in  the  transmission  of  these 
drawings,  the  circumstance  that  the  authorities  at  Trieste 
who  exhibited  at  the  Vienna  exhibition  the  objects  in  ques- 
tion were  able  but  recently  to  obtain  a  description  of  the 
fog-horn. 

"  While  the  undersigned  has  the  honor  to  communicate 
to  the  Envoy  the  above  fact,  he  begs  further  to  state  that 
the  Minister  of  Commerce  would  gratefully  acknowledge  the 
courtesy  should  Major  Elliot,  in  return  for  this  collection, 
place  the  Imperial  and  Royal  Government  in  possession  of 
the  promised  drawings  of  those  safety-signals  which  in  the 
United  States  are  in  use  and  have  attained  such  high  per- 
fection. 


260  EUROPEAN    LIGHT-HOUSE    SYSTEMS 

"  The  undersigned  avails  himself  of  this  occasion  to  renew 
to  the  Envoy  the  assurance  of  his  distinguished  considera- 
tion. 

"  Vienna,  February  22,  1874. 

"  For  the  Minister  for  Foreign  Affairs, 

"  ORCZY." 

Mr.jly  to  ££  "The  undersigned,  Envoy  Extraordinary  and  Minister 
trian  Minister,  plenipotentiary  of  the  United  States  of  America,  has  the 
honor  to  acknowledge  the  receipt  this  morning  of  the  note 
of  his  Excellency  the  Count  Andrassy,  Minister  of  the  Impe- 
rial House  and  for  Foreign  Affairs,  dated  February  22,  accom- 
panied by  a  sealed  roll  of  drawings  and  descriptions  trans- 
mitted by  the  Imperial  and  Royal  Minister  of  Commerce — 

"  a.  Of  the  fog-horn  exhibited  at  Vienna  in  the  year  1873 ; 

"  b.  Of  the  parabolic  reflector  of  Professor  Osuaghi,  ex- 
hibited on  the  same  occasion  ; 

u  c.  Of  the  buoys  in  use  upon  the  Austrian  sea-coast ; 

"  These  drawings  are  to-day  transmitted  to  the  Depart- 
ment of  State  for  Major  Elliot,  of  the  governmental  Light- 
House  Board  at  Washington,  and  will  probably  reach  that 
office  in  time  to  be  used  in  the  preparation  of  his  forthcom- 
ing report. 

"  The  undersigned  begs  to  add  in  reference  to  His  Excel- 
lency's remark,  that  the  Imperial  and  Eoyal  Minister  of 
Commerce  would  gladly  acknowledge  the  courtesy  should 
Major  Elliot,  in  return  for  this  collection,  place  the  Imperial 
and  Royal  Government  in  possession  of  the  promised  draw- 
ings of  the  fog-signals  which  in  the  United  States  are  in 
use,  and  which,  His  Excellency  is  pleased  to  say,  have  attained 
such  high  perfection,  that  the  undersigned  has  received  a 
note  from  Major  Elliot,  dated  the  30th  of  January,  saying 
that  in  a  few  days  a  parcel  would  be  dispatched  to  this  lega- 
tion for  the  Imperial  and  Royal  Ministry. 

"  The  undersigned  has  the  honor  to  present  his  thanks  to 
His  Excellency,  and,  through  His  Excellency's  obliging  inter- 
vention, to  the  Imperial  and  Royal  Minister  of  Commerce,  for 
the  valuable  information  now  afforded  upon  a  subject  so 
interesting  and  important  to  the  commerce  of  the  United 
States,  and  for  their  courtesy  in  furnishing  the  same  to  this 
legation  immediately  upon  its  transmission  by  the  authori- 
ties at  Trieste. 

«  The  undersigned  embraces  this  opportunity  to  renew  to 
His  Excellency  the  assurance  of  his  distinguished  considera- 
tion. 

"JOHN  JAY. 

"  FEBRUARY  23,  1874. 

"  His  Excellency  the  COUNT  ANDR!SSY." 


RSITTT 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  .261 

Plate  L,  which  is  copied  from  the  photograph  sent  me 
by  Mr.  Jay,  represents  the  fog-trumpet  as  I  saw  it  at  the 
exhibition  at  Vienna,  and  the  following  is  a  translation  from 
the  Italian  of  the  description  which  accompanied  it : 

"  Since  the  introduction   of  acoustic   signals,   used  in    Amadi's  fog- 
trumpet. 
America  as  well  as  in  Europe  to  mark  dangerous  points  on 

the  coast  in  foggy  weather,  it  has  become  desirable  to  have 
a  more  perfect  instrument,  an  apparatus  that  can  be  used 
not  only  at  light-stations  in  foggy  weather  and  snow-storms, 
but  also  on  board  of  ships,  especially  on  steamers,  riot  only 
as  an  alarm  but  as  a  signal  for  correspondence. 

"  This  object  has  been  fully  accomplished  by  the  inven- 
tion of  Giovanni  Amadi,  of  the  Technical  Institute  of  Trieste. 
His  trumpet  was  exhibited  at  the  universal  exposition  at 
Vienna,  and  was  awarded  a  medal  of  merit. 

"  This  apparatus,  which  consists  of  a  trumpet,  formerly  Description. 
operated  by  compressed  air,  but  now  directly  by  steam,  is 
provided  with  aa  automatic  distributing  steam-valve,  and 
with  a  special  valve  with  finger-board  (operating  keys)  so  as 
to  produce  sounds  at  will. 

"  The  instrument  has  a  most  extraordinary  power  in  pro-    Power, 
portion  to  its  dimensions  and  to  the  pressure  of  steam  re- 
quired to  produce  the  vibrations  ;  it  can  be  put  up  either 
directly  over  the  boiler  or  separately,  and  connected  with 
it  by  a  pipe,  and  it  can  be  turned  to  any  part  of  the  horizon. 

"  In  addition  to  its  use  as  a  fog-signal  on  shore,  it  may  be 
applied  on  board  of  steamers  of  whatever  steam-power,  and 
is  especially  advantageous  on  board  of  men-of-war. 

u  By  means  of  the  finger-board,  one  is  enabled  to  give  long    Use  of  finger- 
and  short  sounds  at  will  with  great  accuracy,  and  commu- 
nications may  be  made  at  night,  in  fog,  or  in  snow-storms, 
by  means  of  an  alphabetic  formula  similar  to  that  used  in 
telegraphy. 

il  The  trumpet  (shown  in  Plate  L)  is  operated  by  a  steam-    steam-pi, 
boiler  of  eight  horse-power  and  a  pressure  of  twenty-five re 
pounds  per  square  inch. 

"  The  boiler  is  more  than  sufficient  to  produce  thirty  blasts    Boiler. 
in  thirty  seconds,  which  are  audible  at  a  distance  of  fifteen 
nautical  miles  in  clear  weather. 

"  Connected  with  the  boiler  is  a  small  machine,  which  d^1 
operates  the  automatic  distributing  steam- valve  and  can  be ivo  sounds 
so  regulated  that  the  different  intervals  in  the  sounds  dis- 
tinguish the  different  stations  where  trumpets  are  used. 

"  In  the  Technical  Institute  at  Trieste,  where  this  trumpet 
was  constructed,  it  was  very  particularly  tested,  and  the 
government  officers  at  Trieste  testified  that  the  sounds  were 


262 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 


fifteen1  miieseard  pl^ty  audible  at  a  distance  of  fifteen  miles,  the  height  of 
the  trumpet  being  thirty  English  feet  above  the  sea ;  also 
that  when  operated  with  the  finger-board,  the  signals,  accord- 
ing to  Morse's  method,  could  be  plainly  distinguished  at  a 
distance  of  six  nautical  miles. 

Trumpet  placed 

on  Point  Saivore,  "The  Austrian  government  purchased  this  trumpet  to 
operate  it  on  Point  Saivore,  Istria,  after  trial  of  a  smaller 
one  of  the  same  kind  (audible  five  miles)  near  the  light- 
house at  Trieste. 

"A  third  trumpet,  with  a  steam-generator  of  two  horse- 
power, and  audible  eight  miles,  has  also  been  ordered  and 
finished,  and  will  be  put  in  operation  on  board  of  the  light- 
ship anchored  at  Grado." 

The  following  is  a  translation  from  the  German  of  the 
description  of  the  reflectors  before  referred  to,  and,  with  the 
sketch  as  reproduced  in  Fig.  30,  illustrates  clearly  its  prin- 
ciples : 

Fig.  30. 


to  be 
light- 
ship at  Grado. 


Osnaghi's  reflector. 

"PARABOLIC     REFLECTOR     FOR     INTERMITTENT     LIGHTS, 
DEVISED   BY  PROFESSOR  FERDINAND   OSNAGHI. 

a)°aratus°f  the  u  ^he  principal  object  in  devising  this  apparatus  is  to 
collect  as  many  rays  of  light  as  possible  into  a  beam  paral- 
lel to  the  axis  of  the  reflector,  thus  obtaining  the  greatest 
possible  amount  of  light  at  the  points  illuminated  by  the 
beam,  and  by  making  the  best  use  of  all  the  light  produced 
in  one  direction  avoid  the  considerable  loss  which  occurs  in 
most  apparatus  of  this  kind. 

ieuslan° "  c°nvex  u  lst-  Tne  ra^s  are  united  iu  a  beam  by  means  of  a 
plano-convex  lens  placed  in  front  of  the  luminous  focus. 

^spherical  mir-  u  2d.  A  spherical  mirror  is  inserted  at  the  vertex  of  the 
parabolic  surface. 

"According  to  the  laws  of  reflection  from  curved  surfaces, 
if  a  luminous  body  be  placed  at  the  focus  of  a  parabolic 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  263 

reflector,  the  rays  will  be  reflected  parallel  to  the  axis,  but 
the  cone  of  rays  tangent  to  the  circular  riin,  and  all  rays 
within  this  cone,  will  radiate  divergently  and  be  scattered. 
To  bend  these  rays  parallel  to  the  optical  axis  the  piano-  Use  of  i>i.um 

convex  lens. 

convex  lens  is  used. 


u  If  the  vertex  of  the  parabolic  reflector  were  retained 
the  rays  of  light  which,  directly  behind  the  lens,  are  reu-  flector  without 
dered  parallel  by  reflection,  would,  on  passing  through  the 
lens,  be  concentrated  into  its  focus  and  thence  proceed  di- 
vergently, so  that  nothing  would  be  gained  ;  but  if  we 
remove  the  parabolic  vertex  and  substitute  a  spherical  mir- 
ror with  the  luminous  focus  for  its  center,  the  rays  will  be 
reflected  directly  back  through  the  focus,  strike  the  lens  at 
the  same  angle  as  if  they  had  come  directly  from  the  source 
of  light,  and  after  refraction  proceed  parallel  to  the  optical 
axis.  In  this  way  all  the  rays  are  united  in  a  luminous 
beam  of  parallel  rays  of  great  intensity,  and  the  loss  of 
light  is  reduced  to  a  minimum. 

"  Some  loss  occurs  on  account  of  the  apertures  in  the  L..*.S  <>r  ii-i,t. 
parabolic  surface,  through  which  enter  either  the  carbon 
points  of  the  electric  lamp  or  the  burners  of  ordinary  oil  or 
petroleum  lamp,  and  furthermore  from  the  absorption 
which  always  occurs  when  light  is  reflected  from  metallic 
surfaces.  Although  there  is  more  absorption  by  reflection 
than  by  refraction,  it  may  be  asserted  that  this  apparatus 
would  have  an  advantage  over  the  dioptric  Fresnel  lenses 
now  in  use.  for  the  reason  that  it  concentrates  the  entire 
light  into  one  beam,  while  with  dioptric  apparatus  the  rays 
are  collected  into  from  eight  to  twelve  divergent  beams, 
each  of  which  gives  only  an^  eighth  or  twelfth  of  the  total 
light  transmitted. 

u  Flash-lights  which  appear  with  full  intensity  at  certain  ^  Use  in  flash 
intervals  and  then  disappear  require  a  rotation  of  the  opti- 
cal apparatus.  In  the  Fresnel  system  where  there  are  sev- 
eral flash-panels  the  motion  may  be  slow,  for  to  produce  one 
flash  per  minute  the  revolution  takes  place  only  once  in 
eight  minutes  if  there  are  eight  panels.  The  new  appara- 
tus, however,  must  make  a  revolution  in  one  minute  if  it  is 
required  to  show  a  flash  every  minute.  This  accelerated 
motion  can  easily  be  obtained,  but,  as  the  apparatus  is  light, 
finer  and  more  accurate  clock-work  is  required. 

"  The  principal  dimensions  of  this  apparatus  when  adapt-    Dimensions  ..i 

the  reflector  for 

ed  tor  electric  light  are  as  follows  :  use  in  electric 

"  Focal  distance  of  the  paraboloid,  30  millimeters. 
"  Opening  distance  of  the  paraboloid,  375  millimeters. 
"  Diameter  of  the  spherical  mirror,  85  millimeters. 


264  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

"Diameter  of  the  plano-convex  lens,  85  millimeters. 

"Focal  distance  plano-convex  lens,  45  millimeters. 

"  Height  of  axis  of  paraboloid  above  the  bottom  plate, 
280  millimeters. 

"  In  the  vertical  plane  the  paraboloid  can  be  moved  around 
a  horizontal  axis  passing  through  the  focus,  and  in  the  hori- 
zontal plane  it  may  be  rotated  with  its  standards  around  a 
vertical  pivot.  When  ordinary  lamps  are  used  the  dimen- 
sions should  be  increased  to  correspond  with  the  size  of  the 
luminous  body.  Notwithstanding  the  small  size  of  the  ap- 
paratus, it  has  given  very  good  results  with  a  petroleum  - 
lamp,  quite  surpassing  a  fourth-order  Fresnel  apparatus. 
etfSeV1  lisllt  i;  Photometric  tests  showed  that  with  a  paraffiue-candle 
at  the  focus  of  the  reflector  the  co-efficient  of  concentration 
is  21,000,  that  is,  21,000  such  caudles  would  be  required  to 
produce  the  illumination  of  a  plane  surface  that  one  would 
give  at  the  focus  of  the  reflector.* 
use  of  reflector  "  To  use  this  apparatus  for  fixed  lights,  the  rays,  already 

for  fixed  lights. 

concentrated  in  one  parallel  beam,  must  be  converted  into 
a  luminous  disk  by  a  second  reflection.  A  considerable  part 
of  the  original  intensity  will,  however,  be  lost  by  spreading 
the  rays  around  the  entire  horizon.  To  effect  this  the  para- 
bolic reflector  is  placed  in  a  vertical  position  with  the  mouth 
or  opening  upward,  and  the  rays  from  it  are  received  by  a 
set  of  totally  reflecting  prismatic  rings  arranged  conically. 
The  loss  of  light  by  reflection  will  be  but  trifling. 
cost.  "  Nothing  can  be  positively  stated  as  to  the  cost  of  the 

reflector,  but  it  is  certain  that  even  a  large  one  would  not  be 
as  expensive  as  a  dioptric  apparatus." 

Professor  Osnaghi's  combination  of  catoptric  and  dioptric 
agents  is  not  new,  having  been  previously  invented  by  Mr. 
Thomas  Stevenson  under  the  name  of  "  catadioptric  holo- 
photal  reflector,"!  and  has  been  used  in  many  cases  in  Great 
Britain. 

In  Fig.  31  will  be  found  what  I  conceive  to  be  an  illustra- 
tion of  the  professor's  ideas  in  regard  to  a  fixed-light  apparatus. 

In  this  figure  a  is  the  focus ;  &,  the  spherical  mirror  j  c,  the 
plano-convex  lens  ;  d  d',  the  £>arabolic  reflector  ;  e  e  e,  the 
totally  reflecting  prisms ;  pp,  the  carbon  pencils  for  the  elec- 
tric light.  It  will  be  observed  that  the  major  part  of 
the  light  proceeding  from  the  focus  a  of  the  parabolic  re- 
flector impinges  against  and  is  reflected  by  the  surface 
of  the  latter;  that  the  remainder  of  the  rays  are  caught 
and  refracted  by  the  plano-convex  lens  c  ;  that  both  the 

*  This  co-efficient  is  excessive,  and  is,  without  doubt,  an  error. — G.  H.  E. 
t  See  Light-house  Illumination  ;  Thomas  Stevenson,  1871. 


EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

reflected  and  refracted  rays  are  bent  into  a  vertical  beam 
which  impinges  against  the  conical  surface  of  total  reflec- 


265 


.  31. 


Reflector  as  adapted  for  a  fixed  light  illuminating  360°. 

tion  formed  by  the  prisms  e  e  e,  &c.,  and  that  from  this  sur- 
face the  rays  are  uniformly  distributed  around  the  horizon. 
In  this  apparatus  for  fixed  light  a  considerable  loss  of  light    LOSS  of  I^M. 
would  occur — 

1st.  In  the  reflection  of  the  rays  by  the  parabolic  reflector 
and  the  refraction  by  the  piano-con  vex  lens; 

2d.  In  the  passage  of  the  rays  from  the  bottoms  of  the 
totally  reflecting  prisms  to  the  surfaces  of  total  reflection, 
and  thence  to  tho  vertical  sides  of  the  prisms. 

I  should  judge  this  apparatus  to?  fixed  light  inferior  co 
the  dioptric  apparatus  of  Fresnel,  in  which  but  a  single 
agent  is  used. 

The  Austrian  government  had  also  on  exhibition  some 
bell,  mooring,  and  other  kinds  of  buoys,  drawings  of  which 
accompanied  the  drawings  and  descriptions  of  the  fog- 
trumpet  and  reflector  received  through  Mr.  Jay;  but  I 
observed  nothing  else  of  sufficient  importance  to  take  ac- 
count of  in  this  report. 

The  drawings  and  other  information  concerning  our  light-    Drawings  tor 
house  establishment,  referred  to  by  Mr.  Jay  in  his  letter  to  Austria,  -<,v<>rn 
me  of  February  23,  were  some  weeks  ago  forwarded  to  him  m< 
by  the  board,  through  the  State  Department,  for  presenta- 
tion to  the  Ministry  of  Public  Works  of  Austria. 


26 G  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

Diploma  taken     I  should  not  forget  to  mention'  that  the  photographs  and 

by  American  pic-        .     ,.  „  „  ,.    .   .   . 

tures  of  light-  paintings  of  some  of  our  light-houses  occupied  a  prominent 
place  in  the  American  part  of  the  exhibition,  and  it  has 
been  announced  that  they  were  awarded  a  diploma  of  honor. 

^ Kindness  of  Mr.  i  cannot  close  my  account  of  the  exhibition  at  Vienna  with- 
out expressing  my  warmest  thanks  to  the  Hon.  Mr. 
Jay,  the  American  minister,  for  his  great  kindness  to  me  at 
Vienna  and  since  my  return,  as  well  as  for  the  interest  he 
has  shown  in  furthering  the  object  of  my  visit,  particu- 
larly by  his  successful  efforts  to  procure  for  me  from  the 
Austrian  government,  for  publication  in  this  report,  draw- 
ings and  descriptions  of  some  of  the  aids  to  navigation 
which  that  government  had  on  exhibition. 

RETURN  VOYAGE. 

I  sailed  from  Liverpool  in  the  Cuuarcl  steamship  Cuba  on 
the  30th  of  August,  after  an  absence  of  four  months  from  the 
United  States. 
Couversati  on     On  mv  return  vovage  to  America  I  had  several  couversa- 

Avith    Captain 

Moodie.  tions  with  Captain  Moodie,  one  of  the  oldest  and  most  ex- 

perienced commanders  of  the  Cunard  line,  respecting  the 
light-houses  of  Great  Britain  and  the  United  States,  and  an 
interesting  fact  was  mentioned  by  him  in  regard  to  one  of 
the  gas  light-houses  on  the  Irish  coast,  viz :  that  on  the 
night  in  which  we  came  out  of  Saint  George's  Channel, 
the  weather  being  thick,  he  observed  the  light  on  Tuskar 

gas-Sight!  B  Rock  at  a  distance,  as  he  supposed,  of  six  miles,  judg- 
ing by  his  former  experience  with  this  light,  but  when 
he  had  come  up  to  it  he  found  he  had  run  more  than  twelve 
miles  after  he  first  observed  it.  He  subsequently  found 
(probably  when  we  stopped  at  Queenstown  for  the  mails) 
that  since  his  last  voyage  the  light  had  been  changed  from 
oil  to  gas,  and  he  remarked  that  he  was  confident  he  saw 
the  gas-light  at  least  twice  as  far  as  he  would  have  ob- 
served the  oil-light  in  the  same  condition  of  the  atmosphere. 

So55?stack  at  •"•  agked  him  u*s  experience  and  opinion  in  regard  to  the 
low  fog  or  "  occasional ??  light  at  South  Stack,  on  the  coast 
of  Wales,  which  I  have  described,  and  he  stated  he  had 
found  it  of  much  value  when  not  a  ray  could  be  seen  of  the 
upper  light,  which  is  often  obscured  in  fog. 
Aidstonaviga-  Captain  Moodie  thought  our  lights  efficient  as  far  as  he 

tioii    neatf  New 

York.  had  observed  them,  and  spoke  particularly  of  the  great 

value  of  the  revolving  light  at  Fire  Island,  on  the  outer 
coast  of  Long  Island,  which  is  the  first  light  ordinarily  made 
by  over-sea  steamers  approaching  New  York,  but  he  is  of  the 
opinion  that  our  aids  for  using  Gedney's  Channel  into  the 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  267 

harbor,  (which  he  says  -cannot  now  be  used  in  the  night- 
time, particularly  in  thick  weather)  are  insufficient,  and 
suggests  that  a  light-ship  should  be  moored  where  the  fair- 
way buoy  is,  inside  the  bar ;  that  the  fair-way  buoy  outside 
the  bar  should  be  replaced  by  a  bell-buoy,  and  that  the 
present  light-ship  should  be  moored  north-northwest  from 
her  present  position  and  into  line  with  the  bell-buoy  and  the 
light-ship  inside  the  bar. 

Captain  Moodie  mentioned  the  difficulties  of  entering  the    Buoyage    of 
harbor  of  New  York  in  the  winter-time  when  the  iron  buoy 8  York. 
are  removed  and  spar-buoys  are  substituted  for  them,  stat- 
ing that  in  harbors  much  farther  to  the  northward  no  diffi- 
culty is  found  in  maintaining  the  larger  buoys  in  position 
in  winter;*  also  the  difficulty  in  making  out  the  positions  of 
the  leading  or  range  light-houses  in  the  day-time  when  snow 
is  upon  the  ground,  and  suggested  that  they  be  painted 
some  dark  color  instead  of  white,  to  better  serve  as  day- 
marks,  a  change  which  has  been  effected  since  my  return. 

Captain  Hoodie's  views  as  to  the  desired  ameliorations 
in  the  system  of  aids  to  navigation  at  the  entrance  to  the 
harbor  of  New  York  are  entitled  to  much  weight,  and  the 
investigation  of  the  subject  which  I  have  made  since  my 
return,  confirms  me  in  the  opinion  that  the  changes  sug- 
gested should  be  made  without  delay. 

CONCLUSION. 

In  concluding  my  notes  of  inspection  of  European  light- 
house establishments,  I  will  call  the  attention  of  the  Board  to      x 
those  points  which  I  think  are  of  especial  importance  in  the 
foregoing  report,  and  which  I  commend  to  its  most  careful 
consideration : 

(a.)  As  the  subject  of  first  importance,  I  will  mention  the  superiority  of 
superiority  of  the  English  and  French  light-house  lamps  g 
over  our  own.  it  will  have  been  observed  that  while  the 
power  of  our  light-house  lamps  is  fixed,  (i.  e.,  they  give  only 
the  same  amount  of  light  in  foggy  and  thick  weather  as  in 
fair,  in  the  long  twilights  of  summer  as  in  the  darkness  of 
the  night.)  the  English  oil-lamps  are  flexible  in  power,  and 
can  be  varied  by  the  keepers  to  suit  the  varying  conditions 
of  the  atmosphere ;  that  the  first-order  sea-coast  lights  of 
England  may  be  raised  from  an  equivalept  of  342  (their 
minimum)  to  722  candles,  while  the  maximum  power  of  our 
first-order  sea-coast  light  is  uniformly  the  equivalent  of  only 

*  I  do  not  think  this  would  be  possible  in  the  harbor  of  New  York 
without  great  loss.  The  ice-fields,  moving  with  great  velocity  in  the 
spring,  carry  off  any  buoys  which  may  be  placed,  and  spar-buoys,  which 
are  inexpensive,  are,  for  this  reason,  used  in  winter. 


268  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

210  candles  ;  that  while  the  English  and  French  lights  have 
.  been  in  recent  years  increased  iu  power,  the  actual  consump- 
tion of  oil  per  unit  of  light  has  been  decreased  by  improve- 
ments in  the  supply  of  oxygen  to  the  flame  ;  and  that,  if  the 
modifications  which  I  have  described  in  detail  should  be 
adopted,  we  should  increase  the  illuminating  power  of  our 
light-houses  more  than  50  per  cent.,  which  would  be  of  in- 
calculable benefit  to  commerce,  particularly  in  ;'  thick  " 
weather. 

use  of  mineral-  (ft.)  The  European  governments,  after  careful  and  pro- 
tracted experiments,  are  rapidly  adopting  the  use  of  mineral- 
oil  instead  of  the  vegetable  and  animal  oils  formerly  used. 

France  has  been  the  first  to  order  the  burning  of  the  new 
illuminant  on  all  of  its  coasts,  and  the  light-house  lamps  of 
nearly  all  other  nations  of  Europe,  (including  Great  Britain,) 
the  nations  of  the  East,  and  of  South  America,  indeed  all 
that  I  could  hear  of  except  our  own,  are  being  changed  for 
its  use. 

Mineral-oil  is  more  cleanly  than  the  lard-oil  consumed  in 
our  light-houses;  it  is  not  injuriously  affected  by  the 
severest  cold;  the  lamps  are  more  readily  lighted,  and 
do  not  require  to  be  trimmed  during  the  longest  nights, 
thus  making  commerce  less  dependent  on  the  watchfulness 
of  the  keepers ;  while  its  cost  is  but  little  more  than  one- 
third  the  cost  of  the  latter. 

The  use  of  mineral-oil  in  the  multiple- wick  lamps  used  in 
light-houses  was  not  possible  until  the  introduction  of  the 
'  double  outer  current  of  air  to  the  flame,  and  the  invention 
of  the  mineral-oil  light-house  lamp,  (to  whomsoever  it 
belongs,  whether  to  Douglass,  Lepaute,  or  J)oty,)  has  pro- 
duced, without  doubt,  the  greatest  improvement  in  light- 
house illumination  since  the  invention  of  the  Fresnel  lens. 

There  can  be  no  doubt  that  the  adoption  of  this  oil  by  the 
United  States  for  use  in  our  light-houses  would  stimulate 
our  refiners  to  produce  an  article  which  would  fill  the  re- 
quirements which  I  have  mentioned  in  this  report ;  but  if 
they  cannot,  or  will  not,  we  can,  as  I  have  observed,  import 
precisely  the  same  excellent  kind  of  mineral-oil  (Scotch) 
which  is  now  used  in  the  light-houses  of  France  and  Great 
Britain,  and  save  more  than  fifty  thousand  dollars  per  an- 
num, besides  producing  more  reliable  lights  than  we  now 
have. 

housfisadmmi8-     (c>)  Jt  wil1  nave  attracted  attention  that,  as  in  our  service, 
tration    simpler  the  light-house  establishments  of  Europe  are  under  those 

and  more    econ- 
omical than  our  departments  of  government  which  correspond  to  our  Treas- 
ury Department ;  also  that  there  the  administration  on  the 


EUROPEAN    LIGHT-HOUSE    SYSTEMS.  269 

sea-coasts  is  much  more  simple  and  economical  than  our 
own,  and  that  while  in  our  service  the  law  provides  that 
there  shall  be  two  officers  in  each  of  our  twelve  light-house 
districts,  in  Great  Britain  and  France  there  is  but  one  offi- 
cer for  each  district;  that  the  officer  whose  duty  it  is  to  con- 
struct and  keep  the  light-houses  and  the  lenticular  and 
other  parts  of  the  illuminating  apparatus  in  repair  and  to 
instruct  the  keepers  in  the  use  of  the  latter,  is  also  the  one 
to  inspect  the  light-houses.  Were  the  salaries  of  these  offi- 
cers the  only  consideration,  it  would  not  be  a  matter  of  much 
moment,  but  the  dual  arrangement  in  use  in  our  service 
since  1852,  involves  double  sets  of  clerks,  double  expendi- 
tures for  rent  of  offices,  fuel,  and  other  contingent  items, 
for  the  service  of  the  districts,  which  require  an  annual  out- 
lay of  many  thousands  of  dollars,  while  the  service  can, 
there  is  no  doubt,,  be  conducted  with  more  efficiency  and 
economy  *  than  now,  by  a  single  officer  in  each  district. 
This  would  correspond  to  the  practice  of  France,  which  Administration 

1  '  of  French  lights. 

was  the  first  to  adopt  a  thorough  and  scientific  light-house 
system,  and  which  is  surpassed  by  no  other  country  in  the 
science,  simplicity,  economy,  and  efficiency  of  its  adminis- 
tration. The  entire  management  of  the  French  lights  (except 
as  regards  the  appointment  of  the  keepers,  which  is  in  the 
hands  of  the  prefects  or  civil  officers  of  the  districts)  is  in 
the  officers  of  engineers,  (des  ponts  et  cliaussees,)  who  are 
charged  with  the  other  works  of  river  and  harbor  im- 
provement; and  while  there  are  many  other  points  in  which 
we  are  excelled  in  regard  to  the  abov7e-named  qualities  of 
good  administration,  it  is  hardly  required  of  me  that  I  call 
attention  to  them  here. 

(il.)  I  would  call  attention  to  the  desirability  of  modi-  and 

fying  a  few  of  those  of  our  light-houses  on  which  the 


*  From  information  derived  from  the  excellent  Memoire  sur  V  ficlairage 
des  Cotes  dc  France  by  M.  Reynaud,  Inspector-General  of  the  Engineer  Corps 
des  Ponts  et  Chausse'es,  and  Chief  of  the  French  light-house  establishment, 
and  from  other  sources,  I  find  that  the  combined  illuminating  power  of 
the  French  lights,  expressed  in  French  units  of  light  t,  is  2199,  and  the 
expense  of  the  cost  of  maintenance  is  about  $52.20  per  unit  per  annum. 

The  total  illuminating  power  of  the  light-houses  of  the  United  States 
is  2233  units  of  light  t,  uud  the  cost  of  maintenance  is  $401.50  per  unit  per 
annum,  or  about  eight  times  the  corresponding  cost  of  the  French 
lights.  In  the  calculations  from  which  I  have  obtained  these  results,  I 
have  not  taken  into  account  the  cost  of  the  erection  of  new  light-houses, 
the  repairs  of  existing  ones,  the  expenses  of  the  few  light-ships  of  either 
service,  nor  the  cost  of  the  buoyage  of  the  harbors. 

t  This  is  an  aggregation  of  the  powers  of  the  naked  flames ;  that  is,  before  con- 
densation of  the  light  by  the  lenticular  apparatus. 


270  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

safety  of  life  and  treasure  especially  depends,  for  the  in- 
troduction of  the  electric  and  the  gas-lights,  w  iich  I 
have  described  in  great  detail,  since  there  are  now  many  of 
these  lights  in  use  in  Europe,  and  I  think  we  should  not  be 
behind  any  nation  in  our  efforts  to  lessen  the  dangers  of  the 
coasts. 

Kas'and ^lectSc     ^  w^l  have  been  observed  that  the  uncondensed  beams 
n~ht-  of  each  of  these  lights  is  equivalent  to  more  than  the  com- 

bined light  of  2,000  caudles,  while  our  maximum  sea-coast 
oil -lights  are  but  little  more  than  an  equivalent  for  the  light 
of  200  candles.  There  is  no  light  which  can  penetrate  a 
dense  fog,  but  there  is  the  multitude  of  intermediate  con- 
ditions of  hazy  and  thick  weather,  between  fair  weather 
on  the  one  hand  and  dense  fog  on  the  other,  which  can  be 
illumined  by  such  lights  as  that  which  I  saw  at  Souter 
Point,  on  the  east  coast  of  England,  and  which  flashes  over 
the  North  Sea  its  condensed  beams,  each  of  which  is  more 
than  equivalent  to  the  combined  light  of  800.000  candles ! 
^oost  of  chang-  The  cost  of  changing  at  a  sea-coast  light-house  from  oil 
to  either  gas  or  electric  light  is  not  great,  and  it  was  stated, 
as  I  have  mentioned,  that  the  cost  of  maintenance  of  the 
gas-light,  of  which  Professor  Tyndall  spoke  so  highly  when 
in  the  United  States,  is  less  than  the  cost  of  maintenance 
of  the  oil-light. 

of^cd  and  white  («•)  I  should  also  mention  the  inequality  which  Professor 
S?g  ienseSrevolv'  Tyndall,  the  scientific  adviser  of  Trinity  House,  has  estab- 
lished between  the  red  and  white  panels  of  revolving  lenses 
in  the  English  light-houses,  as  mentioned  under  the  heads 
of  "  The  Wolf "  and  "  Flamborough  Head  "  lights.  In  order 
that  the  red  may  be  seen  at  the  same  distance  as  the  white 
flashes,  the  English  revolving  and  flashing  lenses  are  now 
made  so  that  the  areas  of  the  red  and  white  panels  are  in 
the  proportion  of  21  to  9. 

In  the  United  States  the  red  are  of  the  same  size  as  the 
white  panels  in  the  same  lenticular  apparatus,  and  the  result 
is,  that  the  white  are  seen  at  a  much  greater  distance  than 
the  red  flashes  ;  so  that  when  a  red  and  white  flashing  light 
first  appears  above  the  horizon  it  is  liable  to  be  mistaken 
for  a  white  flashing  light  on  another  part  of  the  coast  and 
lead  to  disaster. 
Ability  to  work  (/'.)  An  improvement  upon  our  service,  to  which  I  have 

revolving  lenses        Ni/    ' 

by  hand.  called  attention,  is  the  ability  of  the  keepers  of  a  revolving 

or  flashing  light  to  revolve  the  lens  by  hand  if  the  ma- 
chinery should  become  disabled. 

(g.)  I  would  especially  mention  the  practice,  of  which  I 
saw  many  cases  on  the  coast  of  England,  of  marking  out 


EUROPEAN   LIGHT-HOUSE    SYSTEMS.  271 

dangers  and  important  channels  in  the  neighborhood  of 
light-houses  by  means  of  "  red  cuts."  A  marked  instance 
of  the  utility  of  the  system  will  be  found  under  the  head  of 
Coquet  Island. 

(h.)  The  plan  of  utilizing  the  rear  light  of  light-houses,  or    utilizing    <>t 

7        landward  light. 

that  which  would  otherwise  be  thrown  and  wasted  upon  the 
land,  is  mentioned  at  several  places  in  the  foregoing  report, 
and  an  application  of  the  system  by  furnishing  a  low  or  occa- 
sional light  at  our  elevated  stations  on  the  Pacific  coast,  where 
the  lights  at  the  summits  of  the  towers  are  often  obscured 
in  the  fog-clouds,  when  it  is  clear  below,  has  been  suggested 
under  the  head  of  Souter  Point. 

(i.)  The  rules  of  the  European  light-house  establishments  Light-keepers. 
in  regard  to  the  appointment  and  promotion  of  keepers,  on 
whom  the  utility  of  light-houses  and  the  safety  of  life  and 
property  so  largely  depend,  are  fully  described  in  the  report, 
and  the  facts  are  noted  that  for  each  light  the  number  of 
keepers  is  smaller  than  in  our  service ;  that  they  are  fur- 
nished with  circulating  libraries  ;  that  their  pride  in  their 
profession  is  stimulated  by  being  furnished  with  a  hand- 
some uniform  dress ;  that  they  are  promoted  for  merit ;  that 
they  are  educated  with  care  for  the  management  of  lights 
before  they  are  intrusted  with  the  charge  of  them ;  that  their 
lives  are  insured  for  the  benefit  of  their  families,  and  that 
they  are  pensioned  when  superannuated  ;  none  of  which  ob- 
tain in  our  own  service. 

(j.)  The  improvements  suggested  by  Captain  Moodie,  of    Aids  to  uaviga- 

.  ,  .  . '   .      tiou,  New  York 

the  Cunard  Company,  in  regard  to  aids  to  navigation  at  the  harbor, 
entrance  to  the  harbor  of  New  York,  deserve  attention ;  also 
the  fact  of  the  insufficiency  of  fog-signals  and  lights  on  over- 
s,ea  steamers,  which  I  have  mentioned  in  the  first  part  of 
my  report. 

(k.)  The  maritime  nations  of  Europe  find  no  difficulty  in  the    Revolving 
use  of  revolving  lights  and  efficient  fog-signals  on  light-ships,  iilnSs^ 

It  is  well  known  that  a  fixed  is  less  powerful  than  a  re- ships> 
volving  light,  which  more  readily  arrests  the  eye  of  the 
mariner  who  is  approaching  the  coast,  and  we  have  many 
of  them  at  our  shore-stations,  but  we  neither  have  revolving 
lights  nor  fog-signals,  except  bells,  on  our  light-ships. 

It  is  an  important  fact  to  be  noted,  that  of  43  light-ships 
around  the  coast  of  Great  Britain  30  of  them  have  revolving 
lights. 

(1.)  I  would  also  call  attention  to  the  method  of  marking    Buova,,e 
buoys,  and  the  importance  which  is  attached  in  England  to 
frequently  renewing  the  number  and  name  of  each  buoy, 
so  that  they  shall  always  be  distinctly  visible ;  to  the  prac- 


272  EUROPEAN    LIGHT-HOUSE    SYSTEMS. 

tice  of  making  the  size  of  the  white  checkers  or  stripes  on 
parti-colored  buoys  about  20  per  cent,  less  than  the  black 
or  red,  it  being  found  that  the  characteristic  distinctions  of 
the  buoys  are  better  preserved  by  this  inequality,  and  also 
to  the  plan  of  marking  the  different  sides  of  channels  by 
buoys  of  different  shape  as  well  as  color,  so  that  they  can  be 
more  readily  distinguished  at  night  and  in  thick  weather. 

In  my  preliminary  report  I  mentioned  my  obligations  to 
Mr.  Pelz,  chief  draughtsman  of  the  Board,  and  I  cannot 
close,  without  again  tendering  to  him  my  sincere  thanks  for 
his  zeal  and  interest  in  preparing  for  publication  the  plans 
and  other  drawings  which  I  obtained  in  Europe  ;  also  to  Mr. 
Baker,  the  talented  financial  clerk  of  the  Board,  for  his  excel- 
lent translations  of  the  French  papers  which  are  found  herein, 
and  for  his  valuable  assistance  in  the  preparation  of  this 
report  for  the  press. 


INDEX. 


A  CCIDENTS  from  use  of  mineral-oil,  194, 
A     195,  198 

—  to  electric  light  at  La  Here,  233 

—  provision  against,  at  Grisnez,  225 

Haisborough,  105 

Howth  Baily,  159,  162 

—  La  Heve,  223,  225,  232 

—  Souter  Point,  122 

—  South  Foreland,  70 

Wicklow  Head,  161,  165 

in  gas-light  apparatus,  162, 164 

Acid,  used  for  removing  sea-weed,  147 
Administration,  light-house,  foreign,  supe- 
rior to  that  of  the  United  States,  268 

Aids  to  navigation  New  York  Harbor,  266, 

271 
Air,  how  admitted  to   English  lanterns, 

107,  154 

at  the  Wolf,  143 

Air-tubes,  Douglass  burner,  77, 82, 86, 151 

—  Doty  burner,  74 

—  Farquhar  burner,  206 

—  Fresnel  burner,  208,  212 

—  Lepaute's  1845  burner,  209,  212 
truncated-cone  burner,  210.  212 

modified  Fresnel  burner,  210,  212 

Allard,  M.,  185,  193 

drawings  received  from,  225 

Allen,  Mr.  Robin,  19 

Allowances  to  keepers,  English  service,  98 

French  service,  216 

Scottish  service,  177 

Auiadi's  fog-horn  at  Vienna,  261 
American  lights,  opinion  of  Captain  Mc- 
Cauley,  15 

—  Moodie,  266 

—  burners  compared  with  Douglass's,  88 
Anchors  for  English  light-ships,  93 
buoys,  96 

Anglesea,  island  of,  visit  to,  149 
Apparatus,    catoptric.     See   Reflector-ap_ 
paratus. 

—  dioptric.    See  Lenticular  apparatus. 

—  revolving.     See  Machinery. 

S.  Ex.  54 18 


Apparatus  for  electric  light,  67, 123,221, 

241 

—  gas-light,  75,  104,  159,  160,  161,  162, 

165,  166,  167,  170,  171 
testing  oils,  188 

—  designs  furnished   by  Commission  des 
Phares,  192 

—  prices  fixed  by  Commission  des  Phares, 
192 

—  at  D6p6t  des  Phares,  186 

Industrial  Exhibition,  Edinburgh,  180 

Vienna  Exposition,  251 

Application  de  Vlmile  mlncrale,  <  tc.,  by  M. 
Reynaud,  193 

Appointments  of  keepers,  English  service, 
98 

French  service,  216,  249 

Scotch  service,  177 

boatmen,  Scotch  service,  178 

Arago,  observations  on  sound,  34 

Areas  best  for  red  and  white  panels  in 
flashing  lights,  118,  142,  270 

Areometer,  for  testing  oils,  188 

Argyll,  Duke  of,  cited,  55 

Ar-men,  phare  de,  model  at  Vienna,  250 

Armstrong,  Sir  Wm.,  visit  to  his  ordnance- 
works,  120 

Arnoux,  M.,  215 

Arrow,  Sir  Fred.,  18,  74 

Atmosphere,  eiFect  of,  on  sound,  27. 29, 33, 
38, 40,  41,  43,  44, 46,  49,  50,  51 , 52,  53, 55, 
58,  59, 62 

Austrian  fog-horn,  at  Vienna,  257,  261 

—  government,  drawings  sent,  265 
received  from,  258 

-D ALLYCOTTIN  light,  view  of,  17 

Barbier  and  Fcnestre,  visit  to  manufactory 

of,  206 

agents  for  Doty  burner,  207 

their  articles,  exhibited  at  Vienna 

Exposition,  256 
Basin  for  rain-water  in   lantern-floor  afc 

Haisborough,  107 


274 


INDEX. 


Beacons,  clay,  towers  painted  to  serve  as, 
17,  108 

on  Wolf  Rock,  141 

French  system  of  coloration,  186 

—  illumination  of,' by  gas,  172 

—  French  service  of,  217 
Beazley,  Mr.  M.,  147 
Bell-boat  off  Queenstown.  17 
Bell-buoy,  mouth  of  the  Mersey,  18 

—  Rundlestone,  144 
Bell-buoys,  English,  97 

—  French,  186 

—  Rundlestoue,  144 

Bell  Rock,  light-dues  at,  20 

cost  and  contents  of,  142 

Bells,  signal,  La  Heve,  233 

Bilge-keel  in  English  light-ships,  104 

Bill  of  Port  land  lights,  135 

Bishop  light-house,  cost  and  contents  of, 
142 

Blackwall  depot,  visit  to,  76 

Board,  United  States  Light-House,  extract 
from  report  of,  9 

preliminary  report  to,  9 

sent  siren  for  English  fog- 
signal  experiments,  36 

—  of  Trade,  English,  controls  British  light- 
house affairs,  21 

—  of  Commissioners  of  Irish  Lights,  letter 
from,  158 

visit  to,  158 

Scottish  Lights,  visit  to,  175 

establishmenfc  and  organi- 
zation, 178 

Boat  for  landing,  Wolf  Rock,  143 

Boatmen,  appointment  of,  in  Scottish  serv- 
ice, 178 

Boilers,  best  for  fog-signals,  25 

for  fog-signals  at  Vienna,  261 

La  Heve,  221 

Seven  Stones  light-ship,  146 

Souter  Point,  126 

South  Foreland,  67 

Bonus  paid  French  keepers,  217 

Books,  at  English  stations,  108, 138 

French  stations,  220 

—  Scottish  stations,  176, 177 

Breakwater  at  Holyhead,  149 

Plymouth,  137 

Broglio,  Due  de,  letter  on  French  burners, 
191 

Bronze  for  window-frames,  rock-stations, 
143 

Buoyage,  English  system,  96 

—  French  system,  186 


Buoyage  of  New  York  Harbor,  267 
Buoys,  Coquet,  127 

—  English.  95, 96, 102 

—  French,  186 

—  designation  of,  96, 271 

—  for  strong  tide- ways,  95 
channels,  95 

—  Godrevy,  148 

—  Herbert's,  95 

—  models  at  Vienna,  8 

—  Depot  des  Phares,  186 

—  moorings  for,  96 

—  mouth  of  the  Mersey,  18 

—  Queenstown,  17 

—  Rundlestone,  144 

—  water-ballasted,  95 
Buoy-indicator,  Yarmouth,  102 
Buoy-list,  English,  96 
Buoy-shed,  Blackwall,  97 

—  Yarmouth,  101 

Bureau  des  Longitudes,  experiments  by,  34 
Burner,  Carcel,  the  French  unit  of  light, 

187,  196 
Burners,  comparative  tables  of  old  and 

new  systems,  87, 88, 201, 202, 211 

—  Doty's,  74, 181, 190, 191, 194, 203, 207, 209, 
212, 256 

—  Douglass,  for  colza  and  mineral  oils,  82, 
83, 84, 86, 87, 104, 150, 169, 181, 190 

gas,  79 

—  Farc[uhar,206,251 

—  Fresnel,  for  colza,  199, 208, 209, 212 
gag,  199 

—  Lepaute's,  of  1845,  205,209,212 
truncated  cone,  210, 212 

modified  Fresiiel,  191,203,210, 212, 215 

gas,  215 

paper  on,  208 

—  foreign,  are  superior  to  those  used  in  the 

United  States,  267 

—  means  of  varying  oil-level  in,  207,  212- 
215 

—  received  from  Trinity  House,  89 

—  results  of  improvements  in,  20, 79, 84, 85, 
86,88 

—  Silbe^s  gas,  79 

—  six- wick,  not  used  by  the  French,  189 

—  statement  of  French  Minister,  191 

—  table  of  experiments  with,  81, 82, 83, 84, 
86, 168, 169/170 

—  Wigham's  gas,  75,  104, 159,  160, 161-171 

—  triform,  166, 167, 168, 171 

—  at  Haisborough,  104 
Holvhead,150 


INDEX. 


275 


Burners  at  Howth  Baily,  159 

Vienna  Exposition,  '251, 256 

—  Wicklow  Head,  160 
—  used  in  French  service,  190, 191, 203,  210 
Button,  central,  in  Doty  burners,  74 

Douglass  burners,  74, 81,  86 

gas-burners,  79 

—  Lepaute's  burners,  212, 214 
By-pass  in  gas-burners,  160, 162, 172 


/CABLES,  conducting,  at  La  Heve,  224, 
\J  229 

—  for  English  light-ships,  93 
Cans,  oil,  at  Blackwall,  91 

manufactured  by  Barbier  and  Fenes- 

tre,  206 

Cape  Elizabeth,  lens  manufactured  for,  206 
Carbon-points  used  in  electric  lamps,  68, 

123,  225, 232, 237 

Carcel  burner  the  French  unit  of  light,  187 
Certificates     required     from     applicants, 

English  light-keeper  service,  97 
French  light-keeper  service,  216 

—  given  applicants,  English  light-keeper 
service,  98 

Chains,  English,  terms  of  contracts  for,  93 
Chain-wheels,  used  in  revolving  apparatus, 

150 

.Chance,  Bros.  &  Co.,  manufactory  of,  183 
manufacturers  of  lens  at  Flam- 
borough  Head,  118 

—  Holyhead,  149 
Longstone,  130 

-  Souter  Point,  121 

-  South  Foreland,  68 

-  Wolf  Rock,  142 

Channels,  English  system  of  buoyage,  96 
Chart  of  Coquet,  128 

Souter  Point,  122 

The  Wolf,  141 

Children  of  Scottish  keepers,  instruction, 
177 

Chimney-cap,  Faraday's,  156 

Chimneys,  lamp,  at  Inner  Fame  Island,  130 
—  Douglass's,  87, 151 
-for  gas-light,  105, 162 

modified  Fresnel  burner,  215 

preserving  from  breakage,  119 

srnoke-funnels  for,  214 

test  of,  92 

Church-service  to  be  read  by  English  light- 
keepers,  115 

Clergyman  of  Church  of  Scotland  sent  to 
stations,  177 


Clock-work  of  revolving  machinery,  pro- 
vision for  accident  to,  122 

—  exhibited  at  Vienna,  251 

Coal  used  at  Haisborough  grs-light,  106 

Collinson,  Admiral,  99, 131 

Colza-oil.    See  Oil. 

Commission  des  Phares,  visit  to,  184 

executive  officers,  185 

furnishes  designs  for  apparatus, 

192 
fixes  scale  of  prices  for  apparatus, 

192 

—  of  Irish  Lights  introducing  gas,  104 
visit  to,  158 

Scottish  Lights,  175, 178 

Conducteur,  French  service,  218 
Consumption  of  carbon-points  at  electric 

lights,  123 

gas,  Douglass  burner,  79 

-  Wighatn  burner,  106, 163, 165, 169, 

173 

—  oil,  comparative,  81, 82, 83, 86, 87, 182, 

190,196,198,201,211 

tested  in  English  service,  90 

Doty  burners,  195. 198, 201 

Douglass  burners,  83, 87, 190 

—  Lepaute's  burners,  190, 191, 211 

fuel,  electric  lights,  67 

Coquet  Island,  description  of  light  at,  127, 

-chart,  128 

division  of  area  around,  129 

Corporation  of  Trinity  House,  20 

Corps  des  Pouts  et  Chauss6es  in  charge  of 

the  administration  of  the  French  light- 
house service,  185 

models  exhibited  by  them  at 

Vienna,  250 
Cost  of  change  to  electric  light  at  La  Heve, 

241 

of  oils  in  France,  203 

colza  and  mineral  oils,  88, 190 

dovetailing  stone  at  the  Wolfj  141 

English  buoys,  97 

lights,  decrease  in,  18 

—  light-ships,  93 

;  lantern  at  The  Start,  135 

maintenance  of  electric  lights,  245 

gas-lights,  171 

new  French  burners,  191 

repairs  to  machinery  at  La  Heve,  240 

rock  light-houses,  (table,)  142 

station  at  Souter  Point,  125 

substitution,  gas  for  oil,  108,270 

of  electric  for  oil  lights,  72, 270 

— mineral  for  lard  oil,  88 


276 


INDEX. 


Cost  of  unit  of  electric  light,  246 

light  iu  France  and  the  United 

States  compared,  269 

Contents  of  rock  light-houses,  (table,)  142 
Contracts,  English,  for  oil,  89 

ship-cables.  93 

-  French,  for  oil,  189, 197 

Council  chamber,  at  D6n6t  des  Phares,  185 

Cowes,  depot  at,  132 

Crane  for  moving  buoys,  Yarmouth,  101 

setting  up  iron  light-house  tower,  254 

Crew  of  English  light-ships,  pay,  rations, 
pensions,  &c.,  114 
French  light-ships,  249 

—  Seven  Stones  light-ship,  145 
Cunningham,  Mr.  A.,  176, 183 
Cut-off  for  gas,  automatic,  161. 
Cylinder  to  produce  red  cut,  138 
Cylindro  -  conical    burner  of   Henry  Le- 

paute,  212 

DABOLL  trumpet,  on  Newarp  light-ship, 
113 

at  Dungeness,  40, 46 

Day-beacons  erected  on  Wolf  Rock,  141 

—  towers  serving  as,  17, 108 

—  French  system  of  coloration,  186 
Deflector,  interior.     See  Button,  central. 
Deflectors,  arrangement  of,  77 
Delbeke,  Captain,  cited,  243 
Department    of   Public  Works,    French, 

models  at  Vienna,  250 
De"p6t  des  Phares.  visit  to,  185 

—  at  Blackwall,76 
Yarmouth,  101 

—  on  Isle  of  Wight,  132 
Depots  on  English  coasts,  97 
Derham,  cited,  38,  51, 52 

Derrick  used  at  Wolf  light-house,  142 
Diagram,  illustrating  revolving  intermit- 
tent gas-light,  163 
Diameter  of  flames  at  Haisborough,  105 

—  lantern  at  The  Start,  135 

—  English  lantern,  155 

—  wicks  of  new  French  lamps,  201 
Dimensions  of  burners  fixed  by  French 

government,  201, 211 
Dingeys  carried  by  English  light-house 

tenders,  131 
Dinner  at  Lord  Mayor's  of  London,  19, 74 

—  Trinity  House,  132, 149 
Disadvantages  of  electric  lights,  247 
Divergence  of  light  from  large  flames  of 

gas-lights,  105, 170 


Divergence     of    light    from    mineral-oil 

flames,  200 
Doty,  Captain,  interview  with,  74 

claims  of,  74, 191 

compensation  by  Scottish  board,  181 

French  board,  191 

—  burner,  description,  74 

adopted  by  Scottish  board,  181 

gives  same  results  as  the  modified 

Fresnel,  191, 203 

cost  of,  192 

first  brought  forward,  194,209 

patent  purchased  by  Barbier  &  Fe- 

nestre,  207 

variation  of  level  in,  190, 207, 212 

exhibited  at  Vienna  Exposition,  256 

Douglass,  Mr.,  meeting  with,  19 

at  Holy  head,  149 

his  report  on  mineral-oil,  80 

details  of  his  improvements  in  burn- 
ers, 78, 80, 86, 150 

finished  Wo]f  Eock  light-house,  140 

extract  from    his   narrative  of  the 

construction  of  Wolf  Eock,  142 
Douglass  burner,  for  oils,  description  of,  77, 
82, 86, 150 

—  - variation  of  level  in,  82 

results  with,  83, 84, 87, 169, 190 

compared  with  American  light- 
house lamps,  88 

gas-light,  104, 109, 110 

at  Flamborough  Head,  118 

Haisborough,  104 

Holyhead,  150 

value  as  compared  with  Doty 

burner  not  settled,  181 

for  gas,  78 

Dove,  cited,  33 

Dover,  fog-signal  experiments  at,  22 

—  Castle,  pharos  in,  72 

Drawings  furnished  by  M.  Allard,  225 

Austrian  government,  265 

Duane,  Gen.  J.  C.,  extracts  from  his  report 

on  fog-signals,  58 
Duke  of  Argyll,  cited,  55 
Dungeness,  fog-trumpet  at,  40,  46 
Dunkerque  floating-light,  201 
Dwellings,  keepers,  English,  108 

Scottish,  177 

at  Gunfleet,  100 

-  Honfleur,  219 

La  He ve,  241 

Phare  de  PHOpital,  218 

South  Foreland,  66, 71 


INDEX. 


277 


EARTH-CLOSET  used  at  light-stations, 
71 

Echoes,  aerial,  32, 35, 38, 39, 44, 46, 47, 50 
Eddystone,  description  of,  136 
Edinburgh,  Duke  of,  74 

—  industrial  exhibition,  models  at,  180 
Edinundson  &  Co.,  manufacturers  of  gas- 
apparatus  at  Haisborough,  104 

Edwards,  Mr.,  19 

Elder  Brethren  of  Trinity  House,  21 

yearly  inspection  made  by,  131 

Electric  light  at  Grisnez,  225 

Odessa,  226 

Port  Said,  225 

Souter  Point,  120 

on  Westminster  clock-tower,  75 

—  how  produced,  67, 123, 221 

—  lights,  causes  of  irregularity  in,  68, 237 

comparison  with  oil-lights,  72    ^ 

gas-light,  75, 121 

cost  of  maintenance,  72, 239, 246 

machinery  for,  241 

substituting  for  oil,  72, 125, 241, 

270 

unit  of,  246 

disadvantages  of,  247 

intensity  of,  70, 121, 238, 270 

lantern  proper  for,  192, 232, 253 

for  shown  by  Sautter  &  Co.,  206 

—  lenticular  apparatus  proper  for,  121, 
192, 252 

of  the  world,  226 

—  opinion  of  Captain  McCauley,  15 
proper  situation  for,  248 

power  of  penetrating  fog,  121,  126, 

243,244 

range  of,  242, 244 

regulations  at,  English,  125 

recommended  for  the  United  States, 

269 

—  at  La  Heve,  220, 226 

South  Foreland,  66, 70 

Elevator  in  light-house  at  Port  Said,  225 
Emerson,  Mr.,  buoy-indicator  of,  102 
Engine,  caloric,  will  work  the  siren,  62 
Engineer  of  Trinity  House,  19 

Scottish  light-house  board,  178 

—  at  electric  lights,  125 

—  des  Pouts  et  Chausse"es,  185 
Engine-room  at  La  Heve,  221 

—  Souter  Point,  122 

South  Foreland,  66 

at  La  Heve,  227, 236 

replaced  for   more  powerful 

ones,  236 
Souter  Point,  122 


Engines,  steam,  at  South  Foreland,  67 

on  Seven  Stones  light-ship,  146 

Examination  of  English  light -keepers,  97 

French  light-keepers,  216 

Scottish  light-keepers,  176 

Exhibition,  Industrial,  at  Edinburgh,  180 

Vienna,  249 

Experiments  with  fog-signals  at  Dover,  25, 

22 
lights  on  Westminster  tower,  75 

—  colza  and  mineral  oil,  80, 181 , 193, 195, 

196 

new  Douglass  burners,  87 

oil  and  gas-lights,  Haisborough,  110, 

104 

at  Howth  Baily,  167,  152 

Doty  burner,  195 

Exterior  deflector  of  burner,  77 
Extinctions  of  electric-lights,  La  Heve,  233 

TJ1ARADAY,  Prof.,  cited,  151 

wind-guard  invented  by,  156 

Farquhar  burner  at  Sautter,  Lemonnier  & 
Co.'s,  206 

photographs  of  flames  at  Vienna,  251 

Fastnet  Rock,  view  of,  17 

Fatquville,  219 

Feu-de-port  at  Honfleur,  218 

Fire,  means  of  extinguishing,  at  South 
Foreland,  72 

Flag-staffs  at  English  stations,  108, 139 

Flag,  Trinity  House,  displayed,  108, 139 

Flamborough  Head,  description  of,  117 

fog-gun  station  at,  118 

Flames  of  gas-lights,  photometric  values 
of,  170 

mineral-  oil  burners,broader  than  colza 

flames,  194 

brilliancy  obtained,  190,  195,202 

old  and  new  burners,  20 

Farquhar  burner,  photographs  ex- 
hibited at  Vienna,  251 

Flashes  in  eclipse-lights,  efforts  of  Fresnel 
to  prolong,  200 

Flashing-point  of  mineral-oil,  188 

Flexibility  of  gas-light,  111,  267 

Floating  lights,  paperof  M.  Lepaute  on,  204 

apparatus  for,  204 

Fog,  at  Haisborough,  110 

Souter  Point,  126 

—  effect  on  electric  lights,  126,  243,  214 
j sound,  27,  49,  53,  54,  57,  59,  GO 

—  obscuring  high  lights,  123,  157 

—  when  dense,  impenetrable  to  light,  111, 
121,  126 


278 


INDEX. 


Fog-bell,  machinery  for,  constructing  at 

Blaekwall,  93 

Fog-light  at  South  Stack,  157,  266 
would  be  of   advantage  on    Pacific 

coast,  127,  270 
Fog-powers  of  Douglass  burner,  151 

electric  light  Souter  Point,  121 

-La  Heve,  221,  241 

gas-lights,  105 

Fog-signals.    See  also  Sound. 

—  adapted  for  different  localities,  63,  64 

—  best  form  of  boilers  for,  25 

—  site  for,  56,  63,  64 

—  causes  of  fluctuations  in  range,  29,  33, 
38,  52,  53,  58,  59 

—  effective  range  of,  56,  57,  61,  64 

—  intervals  between  blasts,  57,  65 

—  sound-reflectors  for,  179 

—  experiments  near  Dover,  how  conducted, 
22 

signals  used,  22,  23,  61 

pressure  used,  22 

questions  considered,  23 

—  TyndalFs  report,  25 

Sir  Fred.  Arrow's  remarks,  69 

by  General  Duane,  25,  58 

—  American,  opinion  of  Capt.  McCauley, 
15 

—  gun,  qualities  of,  23,  25,  42,  43,  46,  48, 
49,63 

—  reed  instruments,  objections  to,  62 

—  steam-whistle,  qualities  of,  23,  62 

—  best  form  of  bell  for,  25 

—  Austrian  nebelhorn,  257,  261 

—  horns  used  simultaneously,  26 
-DabolFs  trumpet,  40,  42,  46,  113 

—  gong,  113 

-Holmes'  trumpet,  40,  42,  43,  125, 145 

—  siren,  37,  38,  39,  41,  45,  46,  47,  48,  51, 53, 
56,  62 

—  Wigham's  gas-gun,  174 

—  at  Flamborough  Head,  118 

—  Holyhead,  149 
-Howth  Baily,160 

—  Newarp  light-vessel,  113 
Seven  Stones  light- vessel,  145 

—  Souter  Point,  125 

—  South  Stack,  156 

—  St.  Anthony,  137 

—  St.  Catherine,  133 

—  The  Lizard,  140 

—  The  Start,  135 

-Wolf,  143 
in  Scotland,  180 

—  on  light-ships,  113,  145,  27-1 


Fog-signals  on  transatlantic  steamers,  16 
Foundation  for  harbor  light-house,  250 
Four,  phare  du,  model  at  Vienna,  250 
French  light-house  service,  notes  on,  216 
Fresnel,  Augustin,  first  lens  made  by,  186 

concentric  gas-burner  of,  199 

efforts  to  prolong  flashes  in  eclipse- 
lights,  199 
• — burners,  invention  of,  208 

dimensions  and  intensities  of  flames 

from,  209 

air-tubes  and  overflow  in,  208,  212 

French  engineers  hesitate  to  alter, 

199 

modified  by  Lepaute,  210,  212 

Fuel,  tar  used  as,  106,  171 

—  for  French  light-house  keepers,  216 
Fund,  mercantile  marine,  21 
Furniture,  manufactured  at  Blaekwall,  92 

—  allowed  English  keepers,  109 
French  keepers,  216 

/GALLERY,    adjustable,    in     Douglass's 
^  burners,  87 
Doty  lamp,  74 

—  photometric,  at  Blaekwall,  93 
Gang-planks  for  small  boats,  131 
Gardiens  of  French  service,  216 

Gas,  its  use  for  light-house  illumination, 
75, 104, 159, 160, 169, 173 

—  how  manufactured,  106, 159, 160 

—  consumption  of,  79, 106, 166, 169, 171 

—  cost  of,  171 

—  economy  in  use  of,  162, 172 

—  means  of  producing  uniformity  of  press- 
ure, 159 

—  for  illumination  of  beacons,  172 
Gas-burner  of  Mr.  Douglass,  78 

•  —  Fresnel,  199 

—  M.  Lepaute,  215 
Mr.  Silber,  79 

-  Wigham,  75, 104, 159-171 

—  for  triform  light,  166, 167, 168, 171 
Gas-gun  for  fog-signal,  174 
Gas-engine  at  Howth  Baily,  160 
Gas-holder  at  Haisborough,  106 

—  Howth  Baily,  159 

Gas-light  apparatus,  cost  of,  170,  171 

at  Haisborongh,  104 

Howth  Baily,  159 

Tuskar  Rock,  2f>6 

—  Wicklow  Head,  160 

on  Westminster  clock-tower,  75 

Wigham's  patent,  161,  162,  165,  ICC, 

167 


INDEX. 


279 


Gas-light,  comparison  with  electric  lights, 

75, 121 
oil-lights,  104,  109, 167 

—  cost  of  maintenance  of,  182, 171, 172 
substituting  for  oil,  108, 270 

—  divergence  of,  105, 165 

—  experiments  with,  167 

-  flexibility  of,  104,  111,  173 

—  heat  produced  by,  105,  160 

-  intensity  of,  76,  166,  169,  270 

—  less  trouble  than  oil-lights,  161 

—  opinion  of  Professor  Tyndall,  173 

—  power  of  penetrating  fog,  76, 110, 173 

—  at  Haisborough,  104 
-  Howth  Baily,  159 

Wicklow  Head,  160 

—  on  Westminster  clock-tower,  75 

—  recommended  for  United  States  light- 
bouses,  269 

Gas-meters  at  Haisborough,  106 
Gas-referees  of  London,  cited,  112 
Gas- regulator  at  Howth  Baily,  159 
Gas-works,  Haisborough,  106 

-  Howth  Baily,  159 

-  Wicklow  Head,  160. 

Gauge,  for  testing  chimneys  at  Blackwall, 
92 

Gedney's  Channel,  New  York  Harbor,  sug- 
gestions of  improvements  in  the  marking 
of,  266 

Glass,  cylindrical,  for  Ian  terns,  107, 151, 154 

—  used  for  observing  lights,  110 

—  lantern,  broken  by  sea-fowl,  107, 154 
Godrevy  light-house,  description  of,  148 

manner  of  lauding  at,  148 

Gong,  on  board  Newarp  light-ship.  113 
Grace  Darling,  home  and  tomb  of,  131 
Gratuities  allowed  Scottish  light-keepers, 

177 

French  light-keepers,  219 

Gravity,  specific,  of  mineral-oils,  80, 88, 89, 
188, 196, 197 

mineral-oil  required  by  French  con- 
tracts, 188, 197 

—  English  contracts,  89 

Grisnez,  electric  light  at,  225 

Gunfleet  light-house,  description  of,  100 

Gun,  fog,  at  Flamborough  Head,  118 

Gun-metal,  its  use  for  window-frames,  143 


H 


AISBOROUGH,  description  of,  104. 


—  observations  of  oil  and  gas  lights  at, 
109 


Hauois  light-house,  cost  and  contents  of, 
142 

Hawes,  Mr.,  inspector  Irish  lights,  159, 175 

Hawkshaw,  Mr.,  149 

Head  of  Kinsale,  view  of,  17 

Heat  produced  by  gas-light,  105, 160 

electric  light,  252 

six-wick  burners,  189 

—  destroys  ordinary  burners  when  mineral- 
oil  is  used, 83 

Heaters  used  at  American  fog-signals,  146 

Helices  in  magneto- electric  machines,  67, 
227 

Herbert's  Buoy,  95 

Hetling,  cited,  55 

Hoffman,  Colonel,  208 

Holophone,  Stevenson's,  179 

Holophote,  Stevenson's,  179 

Holyhead,  description  of,  149 

Honfleur,  feu-de-port  at,  218 

H6pital;  Phare  de  1'.  217 

Hopkinson,  Dr.,  184 

Howth  Baily,  description  of,  159 

experiments  at,  167 

gas-gun  at,  174 

Humboldt,  cited,  58 

TLLUMINANT,  question  of  the  best,  19, 

J-     190 

Illuuiinants.    See  Electric  light,  Gas-light, 

and  Oil. 

Inner  Fame  Island  light,  130 
Inscription,  Phare  de  1'Hopital,  217 
Inspection,  annual,  made  by  Elder  Breth- 
ren, 131 
Instructions,  to  English  keepers,  97 

—  Scottish  keepers,  176 
Instruments,  meteorological,  atFatouvillc, 

220 
Insurance  on  life  of  English  keepers,  98, 

Scottish  keepers,  177 

Intensity,  comparative,  of  gas  and  electric 

lights,  75, 121, 270 

oil-lights,  104,  109,  167,  169, 

173 

-oil  and  electric  lights,  70,72, 121, 

238, 270 

-  mineral-oils,  80, 196 
and  colza  oil-lights,  81,  82, 

83,85,86,87,181,  190,  195,  198,  1201,202, 

211 

—  lard-oil  lights,  88 

sound,  51 

Dory  burner,  181, 191 , 195, 203 


280 


INDEX. 


Intensity  of  Douglass  burner,  78, 82, 83, 84, 
87, 151 

Farquhar  burner,  206 

Fresnel  burner,  209 

Lepaute's  burners,  210,  211 

—  Wigham's  gas-burners,  75,  110,  166 
169 

—  triform  gas-burners,  75, 166, 169, 170 

—  Maris  lamp,  194 

Irish  Board,  opinion  as  to  use  of  gas,  172 

—  visit  to,  158 

—  lights,  gas  introduced  at,  104 

—  view  of  those  on  the  southern  coast, 
158 


JAY,  Hon.  Mr., 250, 266 

Jets  of  Wigham's  gas-burner,  105, 160 
Junior  Brethren  of  Trinity  House,  21 
dinner  in  honor  of,  132 

KEEPERS,  English,regulations  concern- 
ing, 97 

transportation  of  family,  109 

—  salaries  of,  at  electric  lights,  125 

—  Scottish,  regulations  concerning.  176 

—  French,  to  test  oils,  189 

regulations  concerning,  216 

—  foreign  better  than  those  of  the  United 
States,  271 

—  at  Dungeness,  125 

-  Fatouville,  219 

Gunfleet,  100 

Haisborough,  106 

-  Howth  Baily,  160 

—  Honfleur,  219 
Longstone,  131 

- — Lizard,  140 

—  La  Heve,  221,233 

-  Phare  de  1'Hopital,  217 
-— Sou ter  Point,  125 

—  South  Foreland,  71, 125 

—  St.  Catherine,  134 

—  The  Wolf,  143 

Key  West  light-station,  shadows  cast  by 
sash-bars,  153 

Kinsale,  Old  Head  of,  light-house  as  day- 
mark,  17 


LA  HEVE  electric  lights,  description  of, 
2-20,226 

Lamp-chimneys.     See  Chimneys. 
Lamp-guard  at  Whitby,  118 
Lamp-shop,  Black  wall,  76 


Lamp- valves,  how  made,  206 
Lamp,  Doty.     See  Doty  burner. 

—  Douglass.     See  Douglass  burner. 

—  Fresnel.     See  Fresnel  burner. 

—  electric.    See  Regulator,  electric. 

—  Maris,  description  of,  193 

—  constant-level,  when  used,  194 

—  oil,  used  at  electric  and  gas  lights  in 
case  of  accident,  70,  105,  122,  129,  159, 
162 

—  at  Fatouville,  220 
Holy  head,  150 

—  Souter  Point,  123 
Lamps,  used  for  testing  oil  at  Blackwall, 

90 
different  orders  of  lights,  189,  208 

—  keepers  instructed  in  use  of,  97,  176 

—  changed  semi-monthly  at  French  sta- 
tions, 220 

—  tested  at  D6p6t  des  Phares,  157 
Landing  at  Godrevy,  148 

Wolf  Rock,  142 

Lantern  at  Blackwall,  92 

Gunfleet,  100 

Grisnez,  225 

Holyhead,  151 

- La  Heve,  221,  232 

Souter  Point,  124 

Spurn  Point,  116 

The  Lizard,  124 

—  for  The  Start,  135 

—  model  at  Edinburgh,  180 

—  made  by  Sautter,  Lemonnier  &  Co.,  206 

Barbier  and  Fenestre,  206 

Lantern-gallery,  floor  of,  143 

Lanterns,  for  electric  lights,  71,  107,  125, 

192,  206,  232,  253 

gas-lights,  162 

oil-lights,  151,  192 

light-ships,  92,  205 

—  glass  for,  107,  154,  192 

—  English,  dimensions  of,  71,  155 

have  diagonal  sash-bars,  19,  125,  143 

151 

—  parapets  of,  19,  154,  206 

ventilation  of,  107,  143, 154,  155 

painted  by  keepers,  108 

Lard-oil.  See  Oil. 
Lees,  Mr.,  158,  175 
Lens,  for  verifying  position  of  electric 

light,  222,  232 
Lens-makers,  Barbier  &  Fenestre,  207 

—  Chance  Bros.  &  Co.,  1^3 

—  M.  Lepaute,  204 

—  Sautter,  Lemonnier  &  Co.,  206 


INDEX. 


281 


Lenticular  apparatus,  for  electric  lights, 
19:3,  241,  252 

—  floating  lights,  204,  205,  271 

-  gas-lights,  162,  165,  166,  167 

-  range-lights,  180,  251 

calculated  for  different  heights,  208 

revolving,  worked  by  hand,  122,  270 

proper  intervals  of,  57 

areas  of  red  and  white  panels, 

118,  143,  270 

manufactory  of  Chance  Bros.,  183 

manufactories  at  Paris,  203 

M.  Reynaud  offers  to  test,  192 

at  Coquet,  128 

Fiamborongfa  Head,  118 

-  Holyhead,  149 
Inner  Fame  Island,  130 

-  La  Heve,  223,  226,  229,  232 

-  Plymouth,  138 

—  Souter  Point,  121,  122 
the  Eddystone,  137 

-—  Lougstone,  130 

—  Needles,  134 

Start,  135, 184 

Wolf,  142 

Vienna  Exposition,  251 

-Wieklow  Head,  160 
-Whitby,  119 
—  for  Cape  Elizabeth,  206 

—  Longships  light-house,  184 

—  Swedish  light-ship,  204 

used  at  Howth   Baily  experiments, 

on  Westminster  clock-tower,  75 

Lcpaute,  M.,  visit  to  his  manufactory,  204 

burners  manufactured  by,  191,  203, 

205,209,210,212,215 
paper  on  burners,  208 

—  floating  lights,  204 

articles  exhibited  at  Vienna,  251 

Light-house    administration,    benefits    of 

permanence  in,  183 

English,  vested  in  Trinity  House,  20 

French,  vested  in  Corps  des  Ponts  et 

Chaussdes,  185 
foreign  better  than  that  of  the  United 

States,  271 

—  illumination,   requirements  of,  18,111, 
121, 173 

—  List,  English,  extracts  from,  117,  122, 
128, 134 

Light-houses,  models  at  D6pot  dew  Phares, 
185 

—  Edinburgh,  180 
Trinity  House,  122 


Light-house,  models   at  Vienna    Exposi- 
tion, 250 

—  screw-pile,  99 

—  iron  ft  Vienna  Exposition,  256 
Light-keepers.    Sec  Keepers. 
Light-sbip,  needed  on   Rose  and   Crown 

Shoal,  15 

—  lantern  for,  constructing  at  Black  wall, 
92 

—  design  of  one  for  Sweden,  204 
Light-ships,  apparatus  for,  18,  76,115,181, 

204 

—  bilge- keel  for,  104 

—  moorings  for,  93 

—  regulations  for  English  service,  114, 146, 
French  service,  249 

—  repaired  at  Blackwall,  93 

—  of  iron  no  longer  built  in  England,  93 

—  none  in  Scotland,  181 

—  with  revolving  lights,  271 

Letter  from    Commissioners  Irish   lights, 

158 
the  Due  de  Broglie  to  English  em- 

bassador,  191 

Mr.  Douglass,  79 

-  Hon.  Mr.  Jay,  258 

M.  Reynaud,  190 

Level,  oil  drawn  from  more  than  one,  91 

—  means  of  varying,  212, 214 

—  proper  for  oil  in  burner,  81 
Libraries  at  light-stations,  108, 177 
Lightning-rods  at  light-stations,  108, 138 
Light,  fog,  at  South  Stack,  157 

—  increase  of,  at  Howth  Baily,  159 

—  intermittent,  at  Wieklow  Head,  160 

—  obstructed  by  vertical  sash-bars,  151 

—  utilization  of  the  rear  or  landward,  122, 
271 

Lights,  electric.    Sec  Electric  lights. 

—  gas.    Sec  Gas-lights. 

—  range.    See  Range-lights. 

—  oil.    See  Oil. 

—  American,  opinion  of  Captain  McCauley, 
15 

—  high,  obscured  by  fog,  127,  157,  270 

—  kept  by  English  local  authorities,  20 

—  results  desired  for,  112 
Lime  for  removing  sea-weed,  147 
Liverpool,  docks  at,  18 

Lizard  lights,  description  of,  159 
Longships  light,  description  of,  146 
Longstoue  light,  description  of,  130 
Low  light,  use  of,  .on  Pacific  coast,  127, 

157,  270 
at  Coquet,  127 


282 


INDEX. 


L<!\v  light  at  Plymouth  breakwater,  138 

—  St.  Anthony,  137 

—  Souter  Point,  70, 122 
South  Stack,  157 

—  The  Start,  135,  184 

1U-ACHINE-SHOP  at  Blackwall,  92 

Machine-rooms  at  La  Heve,  221. 
Machines,  magneto-electric,  at  La  Heve, 

221 
South  Foreland,  67 

Souter  Point,  123 

—  polishing,  at  Chance  Brothers',  183 
Paris,  203 

Machinery,  at  La  Heve,  cost  of  repairs, 
240 

—  for  firing  gas-gun,  175 

—  log-hell,  constructing  at  Blackwall, 
93 

fog-bells  in  English  service,  137 

fog-signal,  Holyhead,  149 

Seven  Stones  light-ship,  146 

Souter  Point,  125 

—  South  Stack,  156 

—  St.  Anthony,  137 

—  The  Wolf,  143 

intermittent  gas-light,  162 

—  revolving,  flat  wheels  for,  150 

—  at  South  Stack,  157 
Vienna,  251 

McCauley,  Captain,  conversation  with,  15 
Magnets  used  at  electric  lights,  67,  123, 

227 
Magneto-electric   machines   at  La  Heve, 

221,  227,  236 
South  Foreland,  67 

—  Souter  Point,  123 
Maintenance  of  electric  light,  cost  of,  72 

—  gas-light,  cost  of,  162,  171,  172 
Maltre  de  phare.     See  Keepers,  French. 
"Manacles,  The,"  low  light  at  St.  Anthony, 

to  mark,  137 
Mangon,  M.;  results  of  tests  of,  with  paraf- 

fine,  196 
Manufactory  of  Chance  Brothers  &  Co., 

183 

—  Barbier  &  Fenestre,  207 

—  Lepaute,  204 

—  Sautter,  Lemounier  &  Co.,  206 
Manufactories  near  Souter  Point,  120 
Mapliu  Sands  light-house,  description  of, 

99 

Maris  lamp,  description  of,  190 
Masonry,  comparative  sections  of,  141 


Mast,  steel,  for  lantern  of  light-ship,  92 
Mayor   of  London,  dinner  given  by,  19, 

74 
Measurements,  Seven   Stones  light-ship, 

146 

Media,  glass,  for  observations,  110 
Medicine-chests  at  English  light-stations, 

108 

Members  of  the  Corporation  of  Trinity 
House,  21 

Scottish  light-house  board,  178 

French  light-house  board,  184 

Mercantile  marine  fund,  English,  21 
Mersey,  buoyage  of,  18 
Meteorological    observations   at     South 
Foreland,  72 

on  English  light- vessels,  115 

at  French  light-stations,  220 

Meters,  gas,  at  Haisborough,  106 
Middle  ground  in  channels,  English  sys- 
tem of  buoying,  96 
Mineral-oil.     See  Oils. 
Minot's  Ledge  light-house,  142 
Mirrors  on  French  bell-buoys,  186 
Model  of  Stevenson's  holophoue,  179 
Models  in  De"pot  des  Phares,  185 

—  at  Trinity  House,  122 
Vienna  Exposition,  250 

—  of  light-houses  at  Edinburgh  exhibi- 
tion, 180 

Modified  Fresnel   burners,  chimneys  of, 

215 
description  of,  210 

tables  of,  210,  211 

used  in  the  French  service,  191, 

203 

Moodie,  Captain,  conversation  with,  266 
Moorings  of  buoys,  93 

English  light-ships,  93 

Newarp  light-ship,  113 

Rundlestone  bell-buoy,  144 

Seven  Stones  light-ship,  93, 146 

Morton,  Mr.,  129 

Mucking  light-house,  description  of,  99 

Museum  at  Dep6t  des  Phares,  186 


•VTANTUCRET  SHOALS,  badly  lighted, 

JLl      15 

Naval  review  at  Spithead,  132 

Nebelhoru,  Austrian,  description  of,  257, 

281 

Needles,  The,  description  of,  134 
Netherlands,  Kingdom  of  the,  adoption 

of  Lepaute's  burner  by,  209 
Newarp  light-ship,  description  of,  113 


INDEX. 


283 


New  Castle,  ordnance-works  at,  120 
North  Stack  fog-signal  station,  descrip- 
tion of,  155 
Note  of  fog-signals  most  useful,  38,  39, 

45,  46,  48, 113 


0 


AK,  for  window-frames,  143 


Observation  of  lights  at  Haisborough,- 

109 

Howth  Baily,  167 

light  at  Souter  Point,  126 

Observations,  meteorological,  at  Fatou- 

ville,  220 
South  Foreland,  72 

—  on  English  light-ships,  115 
Odessa,  electric  light  at,  226 
Oil-butts,  St.  Catherine's,  133 

—  South  Foreland,  71 
Oil-cans  at  Blackwall,  91 

—  for  mineral-oil,  206 
Oil-cellars,  Haisborough,  107 
Oil,  foreign  contracts,  89, 197 

—  how  stored  at  Blackwall,  91 

—  cans  for  delivery  of,  91 

—  not  stored  by  the  French,  187 

—  special  trial  of,  made  by  Scottish  keep- 
ers, 17.S 

—  Trinity  House,  purchases  for  other  gov_ 
ernments,  91 

Oil,  colza,  color  and  odor  of,  71 

—  qualities  compared  with  mineral-oil, 
84,  85,  87, 182, 201 

required  by  foreign  contracts,  90, 

389 
results  when  used  with  new  burners,. 

88 

tests  of,  90, 189 

Oil,  mineral,  accidents  from   use  of,  194, 

195,198 
adopted  by  foreign  governments,  19, 

181,190,193,268 
economy  in  use  of,  19, 85,  88, 182, 202, 

268 

—  experiments  with, 20, 80, 181, 193, 195, 
196 

—  qualities  of  different  samples,  80, 196 
as  compared  with  colza-oil,  84, 85, 

87, 182, 201 

lard-oil,  88, 268 

required  by  contracts,  89, 197 

—  tests  of,  89, 90, 187 

cost  of,  85, 88, 182, 190,  ifo 

—  —  precautions  taken  with,  99, 17S,  189 
cans  for,  206 


Oil,  mineral,  regulation  of  overflow,  82, 190, 

207, 212 
Chairman  United  States  Light-House 

Board  on,  195 

Mr.  Douglass  on.  80 

M.  Reyuaud  on,  193 

Ordnance-works  of  Sir  Wm.  Armstrong, 

120 

Orfordness"  light,  description  of,  101 
Osnaghi's  reflector,  262 
Outer  Fame  Island  light,  description  of 

130 
Overflow  of  oil,  adjustment  of,  82, 190, 207, 

212 

PACIFIC   COAST,  suggestions  for  fog- 
lights  on, 127, 157, 270 
Painting  of  towers  and  buildings,  English 

service,  108 
Palmyre,  phare  de  la,  model  at  Vienna, 

250 
Panels,  flash,  for  new  lens  at  Start  Point, 

184 
proper  ratio  of  red  and  white,  118, 

142, 270 

Paraffiue.     See  Oil,  mineral. 
Parapet  of  English  lanterns,  19, 154, 206 
Patent,  Doty's,  infringement  claimed,  74 

—  Silber's,  for  gas-burner,  79 

—  Wigham's,  for  gas-lights,  169 
Pelz,Mr.  P.  J.,271 

Pensions  to  English  light -keepers,  98 

light- vessel  crews,  115 

French  light-house  keepers,  216 

Scottish  light-house  keepers,  177 

Permanence  desirable  in  light-house  ser- 
vice, 183 

Phoros  in  Dover  Castle,  72 
Photographs  of  American  light-houses,  at 
Vienna.  266 

Farquhar  burner,  at  Vienna,  251 

Photometer  used  at  Blackwall,  90 

Depot  des  Phares,  187 

by  French  lens-makers,  208 

—  Hopkinson's,  184 

Photometric   experiments,  rooms   for,  at 

Trinity  House,  22 

Blackwall,  93 

D6pot  des  Phares,  187 

Piles,  electric,  formerly  used  at  La  Heve, 

226. 

—  of  Gunfleet  light-house,  100 
Mapliu  Sand  light-house,  99 

Swedish  light-house,  at  Vienna,  257 

Pinnace,  carried  by  English  tenders,  131 


284 


INDEX. 


Plymouth  breakwater  light,  description 

of,  137 

Poe,  Col.  O.  M.,  144 
Point  Bonita,  Cal.,  resembles  Start  Point, 

England,  136 
Point  Roche,  view  of,  17 
Port  Sa'id,  electric  light  and  elevator  at, 

225 
Power  of  burner  for  fixed  gas-light.  169 

English  lights  increased,  78, 85 

first-order  sea-coast  lights,  121 

—  fog-signal  at  Vienna,  261 

—  gas-light  Westminster  clock-tower, 
76 

lens  at  Souter  Point,  121 

light  at  Grisnez,  225 

La  Heve,  221,  238,  242,244 

South  Foreland,  70 

machines  at  South  Foreland,  67 

Souter  Point,  123 

magnets  at  South  Foreland,  67 

Osnaghi's  reflector,  264 

Powers  of  oil  and  electric  lights  compared, 
72, 121, 225 

—  illuminating,  of  oils,  90 

—  gas-lights,  169 

Prices  of  apparatus  fixed  by  Commission 
des  Phares,  192 

for  electric  lights,  241 

oil,  colza,  81, 197 

-  mineral,  85, 88, 89, 182, 190, 197 
•  —  lard,  88 

—  Wigham's  gas-apparatus,  170,  171 
Prisms,  machines  for  polishing,  183,  203 

—  removed  for  triform  apparatus,  166 
—  tested  by  M.  Sautter,  206 


rjUEENSTOWN  HARBOR,  buoyage  of,  17 

Questions  to  be  considered  at  Dover  fog- 
signal  experiments,  24 

EAIN,  its  effect  on  sound,  26,  37,  40,  45, 
46,  48,  50,  52,  59,  60 
Ramsay,  Captain,  U.  S.  N.,  22 
Range,  effective,  of  fog-signals,  56,  57,  61, 
64 

—  of  electric  light,  112,  242,  244 

fog-signal  at  Vienna,  262 

Range-lights,  apparatus  for,  180, 251 

Bill  of  Portland,  135 

—  Fatouville  and  1'Hdpital,  219 

—  Orfordness,  101 

—  Whitby,  118 


Range-lights  on  English  coast,  116 
Rations  for  English  keepers,  98,  114 

French  keepers,  216 

Scottish  keepers,  177 

Ratio  of  areas  of  red  and  white  panels  in 

flashing-lights,  118, 142,  270 
increase  of  lights  by  apparatus,  169, 

264 

Raynolds,  Lieut.  Col.  W.  F.,  144 
Rear  light,  utilization  of,  122,  271 
Red-cuts  at  Coquet,  127 

Godrevy,  148 

Longships,  147 

Orfordness,  101 

Plymouth  breakwater,  138 

Souter  Point,  122 

Spurn  Point,  116 

Start  Point,  (in  new  lens,)  184 

The  Needles,  134 

Whitby;  118 

—  recommended  for  United  States  light- 
house service,  270 

Reflector-apparatus,  for  light-ships,  76, 271 

—  still  in  use  in  English  light-houses,  7G 

—  requires  constant-level  lamps,  194 

—  made  by  the  elder  Stevenson,  179 

—  for  harbor  and  ship  lights,  179 

-> fog-light,  South  Stack,  157 

Dunkerque  light-ship,  204 

—  at  Gunfleet,  100 
South  Stack,  157 

The  Cockle,  115 

Eddystone,  137 

Lizard,  139,140 

Longships,  147 

Vienna  Exposition,  262 

—  Whitby,  formerly  used,  119 
Reflector  for  sound,  23,  58,  179 
Regulations  as  to  care  of  oils,  99, 178,  189 

—  concerning  English  service,  97, 114 
French  service,  216,  249 

Scottish  service,  176 

Regulator,  electric,  at  La  Heve,  230 

Souter  Point,  123 

—  South  Forelaud,  68 

—  gas,  at  Howth  Baily,  153 

—  oil,  in  Douglass  lamp,  82 

—  used  in  fixed  gas-light,  161 

Repairs,  English  keepers  taught  to  make,  98 

—  general,  made  by  superintendents  En- 
glish lights,  131 

—  to  machinery  at  La  Heve,  240 
Report  of  Chairman  United  States  Light- 
House  Board  on  clangers  of  mineral-oil, 
181 


INDEX. 


285 


Eeport  of  Mr.  Douglass  on  oils  and  burn- 
ers, SO 

General  Duane  on  fog-signals,  58 

United  States  Light-House  Board  for 

1873,  extract,  9 

—  Scottish  board  on  lamps  and  oils,  181 

—  Professor  Tyndall  on  effect  of  sash- 
bar  shadows,  152 

—  gas-lights,  163,  173 
fog-signals,  25 

—  preliminary,  to  the  Light-House  Board,  9 
Review,  naval,  at  Spithead,  132 

—  of  troops  at  Dover  Castle,  72 
Revolving  apparatus.    See  Machinery. 
Reynaud,  M.,  meeting  with,  190 

—  offers  to  test  apparatus  for  the  United 
States,  192 

his  paper  on  mineral-oil,  193 

Rings  of  jets  in  gas-burners^  161 

Robinson,  Dr.,  cited,  27, 51, 56 

Rochemont,  M.  Quinette  de,  his  paper  on 
electric  lights  at  La  Heve,  226 

cited   as  to  shadows  of   sash- 
bars,  153 

Roches  Douvres,  phare  des,  model  at  Vi- 
enna, 250 

Rock  light-houses,  sections  of,  141 

examples  in  the  United  States,  142 

cost  and  contents  of,  142 

rations  of  keepers  at,  98, 216 

Rooms  for  engineer  at  French   stations, 
218 

—  photometric     experiments,     Trinity 
House,  22 

Black  wall,  93 

Depot  des  Phares,  187 

—  officers,  South  Foreland,  71 
Rose  and  Crown  Shoal,  needs  to  be  marked 

by  a  light-ship,  15 
Rouen,  visit  to,  215 

Royau,  phare  de,  model  at  Vienna,  250 
Rundlestoue  bell-buoy,  144 


IS 


AILING,  date  of,  9, 15 


Sailing-directions  for  Coquet,  128 

—  Souter  Point,  122 

—  The  Needles,  134 

St.  Anthony  light,  description  of,  137 
—  Catherine  light,  description  of,  133 
Salaries  of  Elder  Brethren  of  Trinity  House, 
21 

—  English  keepers,  98, 125 

light-ship  crews,  114 

French  light-keepers,  216 


Salaries  of  French  light-ship  crews,  249 

Scottish  light-keepers,  176 

Sash-bars,  diagonal,  best  for  electric  light, 
192, 232 

used  in  English  lanterns,  19 

first  designed  by  the  elder  Steven- 
son, 180 

at  Holyhead,  151 

Haisborough,  107 

Souter  Point,  125    . 

Spurn  Point,  117 

—  The  Stack,  135 

—  vertical,  effect  of  shadows  cast  by,  151, 
152, 153 

Sautter,  Lemonnier  &  Co.,  manufactory  of, 

206 

articles  exhibited  at  Vienna,  251 

tests  of  prisms  and  apparatus 

by,  206 
Saving  to  the  United  States  by  adoption  of 

mineral-oil,  88 

new  burners,  88 

Schenck,  General,  22 

Scottish  light-house  board,  members  of,  178 

report  on  oil  and  lamps,  181 

subordinate  to  Board  of  Trade,  21 

when  established,  178 

Screw-pile  light-houses,  Gunfleet,  100 

—  Maplin  Sand,  99 

comparative  cost  of,  101 

Sea-fowl  break  lantern-glass,  107, 154 
Sea- weed,  means  of  removing,  147 
Seven-Stones  light-ship,  description  of,  146 

moorings  of,  93, 145 

Shadows  cast  by  vertical  sash-bars,  151, 

152, 153 

—  sound.    See  Sound-shadows. 
Shoals  off  Queenstown,  how  marked,  17 
Signals  to  vessels  in  danger,  on  English 

light-ships,  115 

Silber,  Mr.,  his  patent  gas-burner,  79 
Siren,  principle  of,  37, 45 

—  superiority  of,  39, 41, 46, 47, 48, 51, 53, 56, 
62 

—  echoes  produced  by,  38, 39 

—  best  pitch  for  note,  47 

—  means  of  rotating  desirable,  56 

—  with  compressed  air,  56, 62 
Skerry vore  light-house,  142 
Smalls  light-house,  142 
Smeaton,  John ,  136 
Smoke-funnels,  Lepaute's,  214 

Sound,  causes  of  fluctuations  in  range,  29, 

33, 38, 52, 53, 58, 59 
acoustic  opacity,  53, 55 


286 


INDEX. 


Sound,  effect  of  changing  direction  of,  41, 

50, 51, 64 

fog-  on,  27,  49,  53, 54,  57,  59,  60, 115 

height  on,  26 

—  pitch  on  range  of,  38,  39, 45, 46, 48 
rain  on,  26,  37,  40,  45,46,48,50,52, 

59,60 

snow  on,  52, 58, 59, 60 

wind  on ,  46, 51 ,  61 

—  intensity  of,  51 

—  reflection,  aerial,  of,  31,  32,  35,  38,  39, 44, 
46,  47, 50,  58, 59 

—  Arago,  cited,  34 

—  Derham,  cited,  38, 51, 52 

—  Dove,  cited,  33 

—  Duke  of  Argyll,  cited,  55 

—  Hetling,  cited,  55 

—  Huinboldt,  cited,  58 

—  Robinson,  cited,  27, 51, 56 
Sound-shadows,  effect  of,  16,  26,  41,  42, 43, 

56, 64, 133 
Souter  Point  light,  description  of,  ISO 

observation  of,  126 

South  Foreland,  fog-signal  experiments  at, 

22 

lights,  appearance  from  Dover  pier,  70 

description  of,  66 

means  of  extinguishing  fire  at,  72 

—  Stack,  description  of,  156 

low  light  at,  157, 266 

Speaking-tubes,  South  Foreland,  71 

—  La  Heve,  223 

Specific  gravity.    See  Gravity,  specific. 
Spectacle  Reef  light-house,  by  whom  built, 

144 
Sperm-candle,  the  English  and  American 

standard  unit  of  light,  81 
Spithead,  naval  review  at,  132 
Spools  of  magneto- electric  machines,   67, 

227 

Spurn  Point  light,  description  of,  115 
Stairs  at  Haisborough,  106 

South  Foreland,  71 

Whitby,118 

Start  Point  light,  description  of,  135 

new  lens  for,  184 

Steamers,  need  of  fog-signals  on,  16 
Stevenson,  Mr.  Thomas,  179, 183 

his  differential  reflector,  179 

apparatus  for  ship  and  harbor 

lights,  180 

—  holophone,  179 
holophote,  179 

—  Messrs.,  engineers  of  Scottish  board,  178 

—  the  elder,  his    lantern   with    diagonal 
bars,  180 


Stone-courses,  Wolf  Rock  light-house,  141 

—  Longships,  147 

Stones,  The,  buoy  off  Godrcvy,  148 
Stores,  Scottish  keepers  report  quality  of, 

178 

Store-houses,  Yarmouth  depot,  101 
Store-rooms,  South  Foreland,  71 
Strata,  moving,  at  St.  Catherine's  light,  133 
Superintendents  of  Trinity   House  make 

repairs,  131 

have  charge  of  tenders,  97 

Supernumeraries  in  English  service,  97, 98 
Swedish  light-house  at  Vienna,  256 

—  light-ship  made  by  M.  Lepaute,  204 
Switches  for  changing  currents  at  electric 

lights,  228,  229 


rPABLE   showing  qualities   of   different 

A     mineral-oils,  80, 196 

—  of  results  of  experiments  with  Doug- 
lass burner  and  different  oils,  81,  82,  83, 
84,  86,  87 

old  and  new  French  burn- 
ers and  different  oils,  198,  201,  209, 210, 
211 

salaries  of  English  light-house  keep- 
ers, 98 

and  rations  of  English  light-ship 

keepers,  114 

, Scottish  light-house  keep- 

ers,  176, 177 

cost  and  contents  of  rock  light- 
houses, 142 

experiments  with  gas-light,  168 

illuminating  powers  of  gas-lights,  169, 

170 

increase  of  intensity  in  eclipse-lights 

by  use  of  mineral-oil,  202 

expenses  of  electric  light  at  La  Have, 

239, 246 

hours  of  illumination  and  the  work- 
ing of  the  engines,  La  Heve,  240 

comparative  range  of  electric  light, 

244 

observations  of  oil  and  electric  lights, 

244 

Tanks,  mineral-oil,  in  Scottish  light-houses, 
178 

French  light-houses,  198 

Tar,  use  of,  as  fuel,  106, 171 

Tenders,  English,  in  charge  of  superin- 
tendents, 97 

description  of,  131 

Test,  for  chain-cables  for  English  light- 
ships, 93 


INDEX. 


287 


Test  of  apparatus  at  Blackwall,97 
—  D6p6t  des  Phares,  187 

offer  of  M.  Reynaud,  192 

at  Chance  Brothers,  184 

Sautter,  Lemounier  &  Co's,  206 

-  —  lights,  at  Haisborongh,  110 

oil  at  Black  wall,  90 

French  light-houses,  189 

Scottish  light-houses,  178 

Tips  for  burners  in  Douglass  lamp,  77, 83, 
80 

—  removable,  83, 86 
Tower  at  Coquet,  129 

—  Eddystoue,  136 
Longships,  146 

—  Plymouth  breakwater,  137 
St.  Anthony,  137 

St.  Catherine  on  moving  strata,  133 

Souter  Point,  124 

-  Wolf  Rock,  141 

—  exhibited    at  Vienna  by    Sautter,  Le- 
monnier  &  Co.,  254 

Towers  as  day-marks,  17, 108 

—  atBlackwall  for  testing  purposes,  97 

—  Haisborough,  106, 107 

Phare  de  ITlopital,  217 

South  Foreland,  71 

Spurn  Point,  115 

—  English     and    American,    comparative 
merits,  106 

Transportation,  English  keepers,  109 
Triform  gas-light.     See  Gas-lights. 
Trinity  House,  London,  18 

—  acts  as  agent  for  purchase  of  oils,  91 

ceased  to  build  iron  light-ships,  93 

corporation  of,  20 

dinuer  given  by,  132, 149 

engineer  of,  19 

lamps  and  burners  received  from,  88 

members  of,  21 

powers  of  superintendents  of,  97 

subordinate  to  Board  of  Trade,  21 

Tripoli,  Canard  steamer,  accident  to,  17 
Trumpet,  DabolPs,  at  Duugeness,  40, 46 

in  Dover  experiments,  42 

on  Newarp  light-ship,  113 

—  Holmes,  in  Dover  experiments,  43,  46 

—  at  Souter  Point,  125 

Seven  Stones  light-ship,  145 

Tuskar  Rock,  view  of,  17 

gas-light  on,  266 

Tyndall,  Professor,  his  opinion  of  gas- 
lights, 104, 163, 173 

sash-bars  obscuring  light,  152 

report  on  fog-signal  experiments, 

25 


UNIFORMS  worn  in  English  light-house 
service,  98,  109,  114,  139 
Unit  of  light,  photometric,  English,  81 

—  French,  187,196 
----  comparative  values  of  French 

and  English,  187 

---  cost  of,  in  France  and  the  United 
States,  269 

—  cost  of,    when  produced  by  elec- 
tricity and  oil,  246 
Utilization  of  landward  light,  122,  271 


TTALVES,  lamp,  made  by  Lepaute,  206 

Ventilation  of  English  lanterns,  107,  143, 

154,  155 

Vestal,  description  of,  131 
Vienna  Exposition,  249 


ALES,  PRINCE  OF,  149 


Walls  at  Longstone,  130 

Spurn  Point,  117 

Watch  of  keepers,  71,  126. 
Watch-room  at  Souter  Point,  122 
-  Phare  de  l'H6pital,  217 

English,  size  of,  71 

painted  by  keepers,  108 

Water  at  South  Foreland,  72 

—  supplied  at  La  Heve,  233 

Washing,  allowance  for,  to  Scottish  keep- 
ers, 177 

Webb,  Captain,  18,  132,  144 

Weller,  Captain,  99,  131 

Westminster  clock-tower,  lights  on,  75 

Wheels  of  revolving  machinery  at  Holy- 
head,  150 

Whistles,  best  form  of  bell,  25 

—  on  steamers  as  fog-signals,  16 

—  qualities  as  fog-signals,  23,  62 
Whitby  light,  description  of,  118 
Wicks,  care  taken  in  purchase  of,  189 

—  concentric,  separation  in  burners,  209 

—  effect  of  different  oils  on,  84 

—  for  French  mineral-oil  lamps,  201 

—  in  six-wick  lamp,  151 

—  tested  as  to  effect  of  combustion  on,  90 

—  used  in  Douglass  burners,  81 
Wigham,  Mr.,  description  of  his  gas-lights, 

161-167 
—  his  apparatus  at  Haisborough,  104 

burner,  used  at  Westminster  clock- 
tower,  75 

gas-gun  for  fog-signal,  174 

—  offer  to  erect  apparatus  in  United 
States,  171 


288 


INDEX. 


Mr.  Wigham,  his  plan  for  illuminating  bea- 
cons with  gas,  17 

Wind,  its  effects  on  sound,  46,  51,  61 
Wind-guard  at  North  Stack,  155 
Wind-vanes  at  English  stations,  108 
Window-frames  at  English  stations,  143 

—  at  the  Wolf,  143 

—  of  low  light-room,  Souter  Point,  122 
Wolf  Rock  light-house,  plans  of,  19 
description  of,  140 


Wood,  used  for  sound-reflectors,  179 
Wrecks,  English  system  of  buoying,  96 

VERMOUTH,  buoy-depot  at,  101 

Young's  paraffine  used  by  French  govern- 
ment, 197 


P7ONE  of  maximum  intensity  in  six-wick 
Li    burners.  78 


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